"will it work" all depends on what you want to run on it. Some software people still run came out of the ark (i.e. 1990s) and wasn't designed properly for Windows, let alone Windows 7 (but of course it's all Microsoft's fault that the original widget designers didn't follow their design framework and went and stuck workarounds in which failed on 7).
Windows 7, 32 or 64-bit, will run comfortably in 2Gb of RAM, and the 4Gb ceiling in 32bit is not likely to be hit noticeably by the average punter.
I'd expect Windows 8 to be 64-bit only, after all the widget manufacturers have got their 64bit versions of software working under Windows 7.
All that said, if you don't want to do anything extensive, then 4Gb RAM and a 32bit Windows 7 will do nicely. There's no such thing as futureproofing yourself in computing (as otherwise the manufacturers would go out of business!), so it's unwise to spend extra on stuff you don't need, as that cash should go on the next machine when you need it. Also, sticking to 32bit would give your legacy apps that little bit extra that they may need to work.