I'm cautiously optomistic about 4E, but the debacle that was 3.x makes me a little skeptical. A lot of the things I've heard about 4E are encouraging though, especially:
1. Less reliance on magic items.
2. Simplified mechanics/math/gameplay. The new monster stat blocks look great. I don't want to sit for several hours before every session writing up statblocks like 3.x demanded. I want the ease of play of a game like Savage Worlds.
3. More freedom built in for DMs- monsters and PCs don't use the same rules, and not every situation will have a rule codified like in 3.x I found that the shackles of things like wealth per level guidelines, assumed EL/CR, NPC and monster statting, and minute detail for things like grappling, attacks of opportunity, etc sucked the fun out of the game, especially when players assume you MUST use all those rules from the book. All of those things need to die a horrible death, and the DM should be encouraged to keep things moving and run the game based on the players trusting the GM more than the ruleset. 4E seems to be moving in that direction, and I'm very happy about that.