careful when you disable the account control... it can cause you problems down the road... some of the installs built to run with vista count on those account controls, and create problems and corrupt installs.
Also, depending on use, OSX could be great, or it could be crap. I work for a publishing company, so I am on both sides of the fence. OS X is awesome when the application exists for it... but there are still limits if you are a die hard windows person... vice versa is true. It all depends on what you need out of an OS.
64 bit has been available for a long time now, and there still isn't a lot of support for it... so I just write it off until I start seeing some changes... I doubt that will be within 2 years though. So personally, I would stay clear. But, some of the manufactorers are sending out the 64 bit, adn 32 bit with OEM... so if you are buying OEM... just buy one that has both 32 bit and 64 bit in teh box... install the one you want. It only downgrades to XP 32 bit though.