Just for lack of time and interest, I lost track of the landscape, so I don't know anymore what distro I'd use. I think I like the Debian family, but now it would have to be some kind of non-Ubuntu newbie distro.
Mint (Cinnamon edition) for ease of use, a very polished desktop, and minimal learning curve coming fresh off Windows.
CrunchBang if you like things clean and mean, actually have work to do, and aren't opposed to learning something.
Debian if you want to forgo everybody else's nonsense and get back to she who is magna mater
to us all.
And Arch if you're dead serious about Linux, want to stop pretending, intend to learn how Linux works from the inside out, and don't mind getting dirty or busting your hump for about the first three months you're using it. If it's still on your machine - and you're actually still using it at the end of six months - you will grok
Linux as few others do...
With the newest version of KDE (now at 4.10) showing so much promise, Suse (the traditional bastion of KDE admirers everywhere) will also be meriting another look once 4.10 becomes their default desktop. Few have done as nice a job of providing a beautiful and well integrated KDE experience as Suse has. And now that KDE's development team has abandoned some of the inadvisable and overly ambitious design directions they've embarked on over the last few years, KDE looks to be back on track. (Even if Linus Torvalds recently ditched it and went back to using Gnome.
If none of that works for you, there are another zillion
or so alternatives to choose from. Like dogs - there's at least one penguin out there for everyone.
Servers are an easier matter IMHO. Two words: CentOS or BSD. End of script.