I have a dual-boot (XPPro32bit/Win7RC64bit) and I rarely boot over to XP anymore. The more I use Win7, the more I like it. I was having problems with AH Lag with it at first.... FR would stay pegged, but typing or changing bases or whatever would have a 5-10 second lag... and I had rubber bullets like crazy. I originally choked it up to Win7 still being in Beta, but then I discovered a setting in bios that was 'throttling back' the processor when not needed to keep it cool and conserve energy. I disabled it and now it works like a champ! I also like the DX10 enhancements (Win7 actually reports DX11) in my FSX... and everything seems smoother and prettier all around.
I've only used Vista on a few different computers (not this one) and even with comparable hardware things seemed 'choppy' and more unresponsive... even simple things like opening up folders and webpages. Win7 isn't like that at all. It's like having all the bells of Vista with few of the performance hits.
With that being said, just a coupld of things to consider:
1> The difference between 3.5GB and 4.0GB is going to be very minute if even noticeable. Even Win7-64Bit reports for me "4.0GB Ram, 3.19GB Usable". Might be compensating for my 512MB video card... might still be a bit buggy as far as memory management goes... either way I don't really care... performance is excellent so I'm not worried about it. If you want a tried and true (and compatible) operating system, don't let that .5gigs of ram deter you from using XP.
2> Win7 is not official. Come April I believe, it will stop working... at which point you'll need to shell out the money to buy the official version, then back-up your data, then reformat and install. Now being you'll have a triple boot system (and especially being that you know at least the basics of linux) this probably won't be an issue for you as you probably do this at least annually anyhow... BUT it's still something to consider.
3> Win7 still isn't fully supported by all hardware and software, and I'm a bit afraid (well not really but maybe a bit concerned) of the security holes that might still exist... so make sure you weigh that in with your decision.
Basically.. it works great.. and so far I love it.. but I wouldn't depend on it just yet.. if you know what I mean!
Good luck
