Intel's enthusiast chips are scheduled to be released 4th quarter of this year, these will be on socket 2011. I'm not quite as sure about AMD's Bulldozer chip but I think the last time I read they were aiming for a summer release. I believe that will be on an AM3+ socket, but I'm not quite positive on the naming, but it will be a new socket and that's about all I know.
As for Nvidia or ATI/AMD, (AMD now owns ATI and will discontinue the ATI name), this is kind of an age old question as to which one is better. ATI/AMD does have some dual processor cards that are probably the best of the best, but because they are well beyond my price range I don't typically follow up on their performance benchmarks to see if they are worth their price, or how hot they run, etc. I think mostly this is a preference thing, but if you prefer Nvidia their new 500 series are pretty good cards. I'm on the fence myself as to whether or not to spend $530 on a GTX 580 or save about $200 on a GTX 570. Supposedly they are going to be releasing a GTX 560 soon that will be more affordable and should be a pretty good mid range card. I don't follow along ATI cards too much but before deciding to go with Nvidia I was considering their newer 6970 or 6950 cards. There is actually a hacked bios that will make a 6950 a 6970...something to consider as well.
If your computer is working fine now and you can get away with just a graphic card upgrade I'd do that and hold off on buying a whole new system until all of the new architectures are released.