Re: Is a 64-bit Windows 7 quicker than 32-bit in itself, as an OS?
When I pondered about 32-bits vs. 64-bits, mainly because I was worried about how my older 32-bit programs would work, my good friend in Britain told me that they were comparable with a 32-lane and 64-lane highway; you can get double traffic on a 64-lane, compared with a 32-lane. But it doesn't really help you, unless yo have the 64-lane car, and the engine to power it.
I've noticed no problems whatsoever, having gone to 64-bits. Everything older works just fine, even some ancient DOS programs. I have noticed a significant increase in speed and, mainly, in both visual and audio quality in games, but that's due to my improved CPU and GPU.
About the speed issue, I'd go with Mike. If you upgrade, do it properly. No idea to raise 10%. I wouldn't really agree about waiting 'til you get to Windows 8, I intend to stay with Windows 7 Professional until end of support, January 2020 - unless I change my mind.
But XP is obsolete, its support will end in April 2014. There's really no idea in investing in it, is there? Be it 32 or 64-bit. In five years, XP will be like Win98 is today - not really usable. Like, you can't enter the Internet with Win98 today, it'll be max 15 minutes and you're dead. Enemy bullets have developed, while defense has been neglected. Like driving a T-Ford on a German Autobahn? Go figure your odds...?
No one could make a greater mistake than he who did nothing because he could do only a little. - Edmund Burke