I read a great thread in a different forum that was 25 pages of "ask a scalper." Something to keep in mind is that the 91 listings on stubhub might only represent 12 pairs of tickets. Scalpers speculate a great deal. That's why you'll see listings pop up on eBay 2 or 3 days ahead of the onsale.
They also eat some tickets, and sell plenty of others at a loss. What they're counting on is that one yuppie douchebag that'll spend $2200 on 3rd row seats for something to impress his skanky girlfriend. Beyond that, concerts aren't a particularly profitable aspect of scalping. They make their money with sports and season tickets. Probably most of what you see online are amateurs. People who bought extras along with their own, and are selling them to recoup their cost.
I've had some great purchases from scalpers, and generally less than face value. Three of us actually scored Maiden tickets for $15 total in Denver a few years back. We actually tipped him the change from the twenty. If nothing else, you can frequently get tickets at face, minus all the service charges. The key is to go to the venue and buy them in person, rather than buy them online.
Buying scalper tickets at the venue is an interesting thing. Even after the show starts, you'll frequently see these guys looking to buy tickets. As for getting a good deal, once it gets close to show time, they'll usually sell you a cheap seat for pretty cheap. IIRC, the price point seems to be about 1/3 of face value. Lower than that, it's more valuable to them as a tax write off. The biggest factor in the whole thing is just being cool to them. If they think you're a dick, they'll eat the ticket and laugh at you. If they think you're a good guy who, maybe offered him a smoke while you dealt with business, he'd like to see you get in. He's probably already earned his money anyway. As with all things, attitude counts a great deal.
As for nostalgia, growing up a friends mom worked for Sears. She'd pull the max tickets a day or two before they went on sale for him. He'd scalp some and sell some to us for face. Most of the 84-87 shows we had first ten rows for.
Also did the camping out thing a few times. Frankly, it sucked balls. Met some cool people doing it, but never got good seats out of it. Our best trick was to go to the Sound Warehouse in the blackest part of town to buy tickets. Not too many Slayer fans hanging out in the hood.