Re: difference between 32 bit & 64 bit
64Bit is great; however, there aren't many applications for 64Bit (yet)....
32Bit is a proven structure, and it's compatible with almost anything you throw at it. You may still be able to install applications on 64Bit but then you won't get the most out of your processor, and it would still operate at 32Bit because the application is not 64Bit compatible.
Example: Microsoft Fingerprint reader keyboard and wireless mouse combo:
Keyboard and Mouse will work on 64Bit, but your fingerprint reader will be left non-functioning because there is no 64Bit driver for it yet. And so on...so forth.
So do your research and then settle on 64Bit. I've tried 64Bit vista before but i'm on 32bit and quite content with it (for now).