I really like Pathfinder. I've been playing it and GMing it for the last year or so.
GMing is great if you run some of the Paizo stuff - the modules are easy to work through and players don't feel like they are getting railroaded like in other modules (we played some 4e D&D stuff and they were complaining about railroading).
Playing is cool as well - I'm currently playing a level 5 Fighter (3) / Cavalier (2) and I've got no qualms with the system.
The think I like the most is that, even though we all have the official print books, you can still quickly look up everything you need rules wise by going to
http://www.d20pfsrd.com/.
All in all, I like Pathfinder.
Now, I've been thinking about running a Fallout Gurps game with my group (the last AP got me interested) but I'd like to try something new altogether. We already tried Paranoia (Success), and Eclipse Phase (Success). Anyone have any other games that are easy to pick up?