The 64-bit version will only be useful for you if you have more than 4GB of memory. If you have 4GB or less, 32-bit will be fine. In terms of which version to go for: if you're a fairly 'normal' user of PCs, Windows 7 Home would be fine: other versions, such as Professional, that are more expensive have features that you probably won't have use for. Whether or not you'll need to reinstall your programs depends on many factors, but I think I'm right in saying - others will know more - that you can't do an 'over the top' upgrade from XP to W7: it would have to be a fresh install, which would indeed involve you reinstalling your programs. Before you make the move, it might be worthwhile checking whether your programs will run under W7.
You may also want to think about whether your PC is 'up to' Windows 7. It really needs a faster processor and more memory than XP did.
Don't dismiss W8 out of hand. It's not necessarily a touch screen oriented operating system, and MS have made many changes to it that allow it to work more like you're used to (and you'd have the latest version of Windows). It did get a fairly negative press originally, but I think many people are now quite happy with it.
I wouldn't recommend waiting for Windows 9 or 10 or whatever...