Another vote for Ubuntu.
I find KDE does a better job of matching up with Windows. You may want to try Kubuntu
If you've got the time to play with it, it may be worth trying both the standard Ubuntu (with GNOME desktop) and Kubuntu (KDE desktop) to see which one you like better. While I agree that KDE may be a bit more "Windows-like", GNOME is probably more stable, so there's a trade-off.
Actually, if you want to try both desktops, just install the standard Ubuntu release, then install the "kubuntu-desktop" package on top of it. Once you've done that, you will be able to choose which desktop environment you want to use from the login screen.