GTK and Qt are pretty fun to program for actually. KDevelop supposedly has a good WYSIWYG editor, but I never tried it. GTK and Qt both have Perl bindings, so GUI programming is insanely fun and easy that way. But anyways.

I mostly agree with Bleys other than that (mostly). Dual-boot is sadly a pretty good idea, and it's not hard to set up. It's easier to transition that way too, so you can keep Win-doze around for the few (very few) things you still miss, for a while, until you love Linux so much you don't need Win-doze any longer.