TK would be my first choice if only because it works on more than one OS (and I spend the bucks for the book). One of the reasons I like perl is because it is OS neutral. I've never worked with the Win32::GUI. I never heard of WxPerl.

I have some simple examples at http://frontiernet.net/~hsweet/programming/TKintro.htm

Time flies like an arrow, fruit flies like banannas