Vista yuk!
Because when I first arrived in Ireland I had limited cash, I was trying to hold off buying a PC until I really needed it. For an IT person 2-3 months was a long time to wait.
I really wanted to save for a Macbook, but I just couldn't wait and my girlfriend wanted a PC and kinda edged me into buying a "normal" laptop a Toshiba with Vista pre-installed.
At first I was like this is ok, but it didn't take long before I started to really hate it. Pretty much for the same reasons everyone else has stated, but Toshiba have this annoying habbit of installing their own software on your machine. The software is so buddy and frustrating to use I disabled it all from starting up with my machine.
I don't understand why the control panel in Vista was changed so much, its stupid and unneccessary. I installed Ubuntu on a previous machine and really liked it, if Ubuntu could easily run Adobe Software there would be no second guessing I'd switch right now, but unfortunately I need photoshop, illustrator, dreamweaver (well I could live without this one).
So for me, as soon as possible I'm going to buy a Macbook I'm so sick of Microsoft and rubbish bloated software.