LoDDoD is really good, if not great. Dopesmoker I've listened to a few times and I don't get the hype for it. Crimson is again in the really good, if not great category.
As far as other really long songs (like north of the 40 minute mark) that I really like:
Fauna - The Hunt (this is 80 minutes long, and with lots of field recording and whatnot, but it's mostly Atmospheric black metal with plenty of ambient passages, maybe I'll feature it in my black metal thread, but I don't think anyone here will like it)
Monolithe - I, II, III, and IV (these are all more than 50 minutes long and fall in to the realm of Funeral Doom with tons of atmosphere, although III and IV dive more in to prog metal territory)
Ephemeral Sun - Harvest Aorta (40+ minutes of nice instrumental Prog Rock with some cool keyboards)