I ran the beta release of Windows 7 in a virtual machine for about a month.  I didn't do much with it but I did compare it against XP and Vista in virtual machines.  Each machine had 512MB of RAM and a 20GB hard drive.  XP was the snappiest and most responsive and 7 was a close 2nd place.  Aero was not able to be activated in the virtual machines.  Based on that positive beta experience I jumped on the chance to install the 7057 build of win7 on a real machine as my main OS!

So far no major complaints.  I'm running 64 bit 7.  I have noticed that hard drives seem to take longer to show up in my computer than they did in XP.  I don't know if this is due to OS differences or due to the way I have my SATA configured in my BIOS.  I had the SATA configured to emulate IDE in the past for some reason but now my SATA is set to AHCI.  You can't change the setting after Windows has been installed unless you reinstall windows.

2GB was more than enough for XP 32 bit.  I rarely, probably NEVER had 1GB in use if all I was doing was VNC, Firefox and Trillian.  With windows7 and Aero turned on with VNC, Firefox and Trillian I've always got a MINIMUM of 1GB in use.  If I also fire up WMP 12 it shoots up to 1.4GB or more.  2GB may become the bare minimum for my windows7 recommendation... some day I might disable the aero to see if that makes a difference but right now I'm really liking the aero.

Tonight I found my first wierd thing in 7.  Aero peek + WMP12 = upside-down-ness.
[URL=http://img379.imageshack.us/my.php?image=20090405win7wmp12peekoo.jpg][img:2a22b466fb]http://img379.imageshack.us/img379/6871/20090405win7wmp12peekoo.th.jpg[/img:2a22b466fb][/URL]