+1 for Win7.
There are a few nvidia issues and I haven't been able to get any brand of serial to USB cable working without going into the devlopment environment, but overall, I think Microsoft have hit the mark with this one.
XP was okay, but the networking, particularly for a frustration-clicker like me, needed a lot of work. Also, the memory had a tendency to "fill up" and require a restart.
I was an apple user for a while, but the day ctrl-option-esc (or whatever it was) failed to kill a program was the last straw for me. My first Mac lasted 4 years and looked and worked the same as the day I got it, my 4th fell to pieces within about 20 months. I am continuously amazed at how they manage to keep an "alternate underdog" status when they are so restrictive in their OS and now top the sales.
Now Asus is my apple - my eeepc 701 survived being outside during the Gap storms, needing only to be blown out with a hairdryer and my full size laptop lives a hard life (was even stolen by the dog one night, found it in her bed the next day) but keeps on ticking
Now that I sound as bitter about apple as a de-programmed cult member, I will stop typing