I have a pretty big gaming library. Come to think of it, "pretty big" might be an understatement. Used to be (before I had kids and financial responsibilities) I'd buy any game that caught my fancy. If it looked even mildly interesting, I'd pick it up, read it in the bathroom, and then stick it on my bookshelf. Nowadays I'm not so free with my cash. Impulse buys are a thing of the past. My money goes towards things like rent, utilities, gasoline, and food.
So despite the fact that I've really only kept up with two or three titles since I "grew up," I still possess an embarrassing collection of RPGs, many of which I've never actually played. But this rumination isn't solely about my regrets as to these long-ignored titles, but rather to the games I'd love to run or play, whether I've done so in the past or not. Unfortunately, there are only so many hours in the day, and even if the time available to me was unlimited, I doubt I'd get a stable of players with just as much free time.
Dungeons & Dragons (3.5)
I get this hankering every so often to play or run a good, old-fashioned D&D game. I can't quite bring myself to run AD&D 2nd Edition... or any prior edition, for that matter. I've come to like the options available in 3.5 too much. It may still be class-based nonsense, but it's a lot more flexible than previous editions.
My all-time favorite setting for D&D is Dark Sun. Outside of Athas.org, there was never and official 3.5 update for Dark Sun. Well... I take it back. There were some Dungeon and Dragon articles back in the day, and they weren't bad (outside of their take on half-giants, IIRC). And the Athas.org stuff is usable, too. If I ever did it, I'd need to take a long look at the available source material and decided which version(s) to use.
Green Ronin's Thieves' World campaign setting, I've never run a game of TW (outside of a couple of sessions at conventions). Between the core setting book and the other supplements, it is such an awesome product line. It's really too bad it didn't sell better, but I guess TW fans who also play 3.5 are nothing if not a niche audience. If you like TW and you don't have the books, I suggest you check out Green Ronin's online store. Last I looked, the gift set was discounted quite a bit.
There are others I could touch on: Green Ronin's Testament (Biblical!), Eternal Rome (Romans!), and Skull & Bones (Pirates!); Mongoose's version of Lone Wolf (which is a bit too rules light as written); and Nyambe (deepest darkest Africa).
So... that's about it for D&D. Next time I'm going to cover some other RPGs I'm hankering to try out, be they pulp, science fiction, horror, or even non-D&D fantasy. See you then!