64 bit is generally better and the driver issues of the past are gone.
If you are using Windows 7 then 64 is the way to go.

i downgraded from 64 to 32bit after i bought my laptop due to driver issues not being compatable with DJing equiptment. 64 bit is only backwards compatable with a handfull of devices. gaming shouldent be a problem with 64bit

I've had no game related problems with Vista 64 (network compatibility issues on the other hand...). If you're installing more than 3GB of RAM, there's really no reason not to use Windows 7 64 as it is the direction everything will be heading sooner than later due to the memory ceiling of 32bit systems.

The only problems you might run into are older peripherals (pre Vista) and applications that are no longer being supported with updates. On a brand new build or even one made in the last two (Intel Core 2 Duo generation onward), I see no reason to stay restricted to 3GB of usable system memory.

Plus from my understanding, both 32 and 64 bit versions are on the Win 7 installer disc. At least I hope so since I've already ordered a copy and there was no selection available for either 32 or 64 bit versions.

ok guys looks like 64 bit is the way to go. How do I backup and restore my files, I've never done it b4 and dont wanna have to reinstall wow and get all my music and saves back. Plus, I will buy a new dx11 card when they come out, but will they work with the little 550watt psu I have?

I bought Acronis True Image Home 2009. I'm restoring a mirror of my start up drive (with all apps installed, etc.) to a larger 1TB drive right now.

If it boots up like before with the restore on the new drive, it will get my thumbs up for anyone looking to do the same.

DX11 cards won't inherently use more wattage; it depends entirely upon the GPU, VRAM and clockspeeds of the components on the card that is DX11 compatible. Naturally a duo GPU card will require more juice than a single (or SLI/Crossfire config naturally).

You could run a GTX285 on a 550w PSU depending on the rest of your system configuration (how aggressive your OC settings are, peripherals, etc.) although most probably wouldn't. Just use a wattage system calculator when you know what the final specs of your system will be.

You can backup the WOW folder entirely by copying it, you never need to reinstall it and go through hours of updates.  I learned this the hard way

If moving from 32 to 64 obviously you cannot use a standard image and reapply as that will be for your original 32 system you can extract data from these images normally though.

The easiest option is to buy a relatively cheap external USB hard drive and copy the information you want to save to that disk. This has the added advantage of acting as a backup media for the future once you get your 64 bit os in place.

kool sounds good

Or you could just wait until Win 7 is released as you will be doing a clean install of your OS.

Acronis did the job for transferring apps and settings (everything but my Steam account settings) from one drive to another although it wasn't the most intuitive utility I've ever used.

But after using the right settings, the same HDD image is now running on a larger drive and I have two bootable versions of the same OS installation along with all apps.

Most importantly; it works for transferring apps across drives. Big thumbs up for Acronis.