[whswhs]

I use GURPS more than anything else, but I've used two other generic games more than once. Big Eyes Small Mouth (I prefer the second edition) is good for games where visual impressions and characterization are more important than precise physical measurements (I've used it for campaigns set in Middle-Earth, on Barrayar, and in an anime-influenced fantasy setting); FUDGE (the original version, not FATE, which I don't care for) is good for games where narrative causality is central (I've used it for a campaign set on the Discworld and for one inspired by Planetary and League of Extraordinary Gentlement). I recommend taking a look at both.

There are also more focused games that I've been happy with: Amber Diceless, Buffy the Vampire Slayer, Mage: The Ascension (2nd edition, not revised, or the recently released anniversary version), and RuneQuest (2nd edition, which I consider one of the great classic RPGs). They can be applied a bit more broadly than their core settings—I used Amber Diceless for a campaign set in E.R. Eddison's fantasy world Zimiamvia—but you have to make sure the campaign you want to run is one that fits their various emphases.