Alright, I guess I might as well get started. True, no reason people can't discuss both.
As a version title, might I recommend something about Weeaboos, or something to the effect of "Japan: The List".
25 - Little Busters!PC - Visual Art's/Key - 2007
We're starting with something extremely weeaboo-y, and a type of game that many of you have probably never played, so I guess a little explanation of the visual novel genre is in order. Typically a visual novel is a japanese game in anime style, most of the game being just text, pictures, music, sound effects, and in newer games, voice acting (and sometimes small amounts of actual animation, but this is pretty unusual). By design, these games tend to focus pretty much entirely on story, because there's not much else to sell a game on...unless it's an Eroge (arrow-gay). This means 'erotic game', and though Visual Novel and Eroge are not equivalent terms, many Visual Novels are Eroge. Some of these suck ass, some of them are pretty great. Though this game is not an Eroge, there are a few on this list, but please believe that in these cases, it's really an in-spite-of thing, rather than a because-of thing. Most of the gameplay in a Visual Novel is choices, either of actions or dialogue. Some of these choices don't really matter, but usually they will influence the plot, specifically, they will lead you onto one of the game's routes - different story paths (and endings) that usually coincide with ending up with one of the game's romantic interests. Most of the time (and in all the ones I've played), you're playing as a guy with female romantic interests. Of course, the inverse also exists (these are referred to as Otome (maiden) Games), and homoerotic ones as well.
So.
Little Busters!, as I have mentioned before, is not an Eroge (though they did release an 18+ version called Little Busters Ecstasy (or EX), which I have not played). As with most games, however, it does have the route structure based on which of the many romantic interests you end up with. First you play through a common route, where you meet all the characters and make choices which determine which girl you'll end up with. The common route focuses on building a baseball team (a convenient way for the game to have you meet all these interesting ladies), and features something relatively rare for a Visual Novel: minigames! The first, of course, is a baseball game. Well, really more of a batting practice game. It's surprisingly complex, you have a lot of control over where the ball goes if you're good at it (I wasn't), and you raise the stats of your teammates by sending the ball toward them. You also can make your pitcher learn new pitches by hitting the baseball at cats (don't ask). The other primary minigame is a battle system, where you are occasionally given an option to 'Wander', which will allow you to challenge other characters to fight you. Although it's pretty random, there is some complexity to it as well, with stats that can be improved through items you earn by winning battles. There's even a secret boss that can be challenged if you complete certain objectives on second playthrough or later (though I've never gotten close, he's insanely powerful). At the end of the common route, you play a baseball game, which you will win or lose depending on the stats you've managed to develop. I won on my first playthrough, but after that I started focussing entirely on combat stats, which I assume is why I lost every single time. Ultimately it doesn't matter if you win or lose, after this game you move on to the route for whichever girl you end up with. After completing all of the routes, you are then able to play through the real ending.
Minigames aside, the main thing that makes this game stand out, of course, is the writing. As usual from Key, it is side-splittingly hilarious, and also soul-crushingly depressing. The characters are also great, mostly anime stereotypes on the surface with hidden (and dark) depths that are revealed in the course of the story. Well, most of them. Futaki's just a bitch I don't care what anyone says. The story is phenomenal, and cleverly integrates the route structure into the narrative itself (can't really explain what I mean without spoiling the whole thing). Writer/Creator/Composer Jun Maeda's music really shines in this game as well.
I don't expect anyone to go out and try this game if they've never played a Visual Novel before (save that for one of the later ones), but if you have ever played and enjoyed one (even, say, Ace Attorney) this is a great one. It has had an anime adaptation, and it's pretty good, but many of the best scenes (both funny and sad ones) are missing, and as with anything else, the original version is better.
24 - Shin Megami Tensei III: NocturnePS2 - Atlus - 2003
So back to the semi-mainstream, this one is a JRPG. If you've never played a Shin Megami Tensei game before, I'm so, so sorry. This one isn't even the best one. Not even close. You're gonna hear a lot about SMT in this list, and if even one of you picks up an SMT game for the first time and enjoys it I will be very glad.
Nocturne is a really great starting point to talk about SMT, though, because as compared to the other games in the series I'm going to mention, it's the most faithful to the basic Shin Megami Tensei formula, that is: You are a person who for whatever story reason has gained the ability to summon demons (in this game it's because you get turned into a half-demon thing), and you must travel around post-apocalyptic Tokyo, befriending and/or killing demons you encounter in battle, and fusing the demons you have into more powerful ones to help you beat the extremely difficult and completely ruthless bosses (MATADOR).
Nocturne is the first (but not last) game in the series to feature the Press Turn system, which in my opinion is the most brilliantly perfect JRPG battle system ever. If you play well, you can abuse the system and win battles. If you play poorly, the system punishes you and you die. Unlike most games in the series (and most JRPGs), though, the secret super-hard boss battle is not THAT hard. I mean, the process of putting Pierce on every demon is grueling, and the process to unlock him is tough, but once you're ready for him he's a pushover, much unlike the nightmares you have to contend with in Digital Devil Saga and Persona, but more on them later.
As any SMT fan knows, one of the best things the series has going for it is composer Shoji Meguro, and this game is no exception. The music fits the tone and aesthetic of the game perfectly, and the boss theme is just the tits, guys.
Unfortunately, the story's a little meh in this one, which is unusual for the series as a whole (in my opinion), but the great gameplay, music, and atmosphere more than make up for it.
23 - The Elder Scrolls IV: OblivionPC/XBox 360/PS3 - Bethesda - 2006
Gonna upset some people, I think, but this is the only Elder Scrolls game on the list. Maybe a bit of nostalgia glasses on this one, but I really love Oblivion. That's not to say I don't love Morrowind and Skyrim (it is to say I don't love the earlier ones, though), but every Elder Scrolls game has its pros and cons. My ideal would be a game with the story of Morrowind, the graphics of Skyrim (or better), and the system from Oblivion. If it weren't for the goddamn thing where you can miss with an attack that clearly hit the target in Morrowind because of a bad roll, it would be the one on the list, instead.
Anyway, what I love about Oblivion is hard to completely pin down. I just feel like it's a good middle ground between the extremes of Morrowind (a hard RPG system wearing an Action-RPG hat) and Skyrim (an Action-RPG that's getting pretty light on the RPG elements). You have stats that matter, but hitting stuff actually matters too. Most of the rest I can say about this game I could say about any modern Elder Scrolls game, the open world is great, and the amount of character customization is excellent. Something I like to do is invent actual characters for my...characters. One guy, a stealthy bow-based assassin character who dabbled in poisons had the internal monologue of a serial killer in my head. I had a character who was a noble knight, and a mage who wanted to become an immortal lich. Again, like any game in the series there are also great unscripted or unintended moments. One of my favourite moments playing Oblivion was hearing the automatic NPC dialogues get a little odd, as one NPC approached another and said, "Hi!", to which the second NPC said, "Hi!". In response, the first NPC said "Bye!", and the second said "Bye!". On the other side of it was when I was doing the last mission for the Thieves' Guild, alone, in the dark, in the middle of the night. I don't know if they intended for the section where you sneak into the tower from underground to be so creepy and imposing, but it was, for me, and I really loved it.
(just an FYI, this is one of only three games on this list that were not made in Japan.)