Do you remember when Microsoft launched XP. "XP's ****!, XP sucks! and so on", the same happened when they released Vista, although Vista somehow deserved it in the beginning, but after a while even Vista have had imporvements and today I would choose Vista, without a doubt.
Why choose between XP and Vista? Why not Windows 7? The new Windows 7 64 bit version is awesome! (compared to Windows in general).
...or you can use Linux (for example Ubuntu).