Only advantage? You missed that a 64-bit OS is more secure from 32-bit viruses and the performance increase of 64-bit applications.
Yeah there are advantages to running 64-bit, and there are a few flavors out there...I have chosen Vista...XP Pro 64 was good, but for me Vista 64 has been a great experience OS wise...better-so than my Vista x86 experience during most of 2007. Stable, feels just as quick as my XP Pro (who cares if it's not with a stopwatch on some things...overall this OS is pretty snappy in my experience with it). Games are FINE for me...if performance is less...obviously it's not enough to deter my gaming experience, I game a lot on this rig.
Really Vista x64 is pretty good...you want my recommendation, if choosing Vista...x64 is the only way to go imo. x64 is the future, a lot of people out there have x64-bit capablity...you can run it fine on 2 gigs...it will let you use all the GB's you can fill in the dimms of a modern enthusiast board and then some on RAM. If you don't like the "extra" goodies, turn em off...some like my G/F likes all that stuff...Vista x64 runs fine on a Core2 6300/Gigabyte P35DS3L/2GB DDR2 1000 Ballistix/Seagate 7200.9 500GB SATA2...her games are no slower, and she said she hasn't noticed a difference in performance with anything she does on her PC. Sure there are those out there, that I will agree with, Vista is slower in some things...but in reality, if it's not something you depend on, or notice.
XP is a good OS, took years to get there...Vista has improved quite a bit imo in the last year, sure Windows 7 is coming soon...I read an article on some PC Magazine site recently that said they've scrapped the MinWin Kernel in favor of using Vista as the base for Windows 7...so if ya don't like it now...you may be just as dissapointed in the future. Maybe Windows 7 is just SP2? Who really knows? That could be completely bunk info.
LINK:
http://www.pcworld.com/businesscenter/article/146525/windows_7_the_story_so_far.html
Sorry for the long post, if it wasn't for Solaris17...I would probably have gone back to Xp 64...good OS, but support just didn't seem there...Vista is udpated, has continuing support, and if what I read was true, is the wave of the future...you'll just get to choose from more flavors (well sorta...I'm sure W7 will be a pretty good improvement).