Try it as I did, on a dual boot. That way if you have issues then you can nuke it.
I assume it should work ok with most of those games. There are a few issues with Vista on a couple of games KOTOR 2 for example - and that in turn translates to issues with W7. However, there are work arounds.
Virtual Dub I know I have working in Windows Vista 64 so I assume will work in W7. Most software is ok, especially if you use the XP compat mode.
http://www.youtube.com/watch?v=FSyqlXEleMQ have a look here if you need an idea of how to dual boot.
DON'T go with 25 gigs though for a windows 7 partition. I would say 80 is a nice size.
I'm already on quad boot ( 2x xp, one that works on sis chipsets, another that works on ALL intel and most nvidia chipsets, 2x vista, one that works on 945p, another that works on 965p) don't want a bigger mess then it is and a new install is absolutely not an option for me, if I have to use a clean install then I might as well not bother I have way too much to reinstall it would take weeks.
So upgrade only or not at all, too much hassle...
oh btw
Something is very fishy about that site, ''install OS'' xp the slowest, that is definitely a lie.http://blogs.zdnet.com/hardware/?p=3236&page=2 here is one link for a second in google. Windows 7 BETA 1 vs Vista AND XP.
.
XP installs within 15-20 mins (on pretty much any modern spec, I have done this many many times), vista took 40( if not more) mins for me ( though I only have experience installing vista 3 or four times). There is no way 13 gb of vista installs faster then like 2 gb of XP.