1. MoBob and me
2. by myself
3. my feet in Brazil
4. MoBob and me at Christmas
These are all very nice pictures! I would maybe start with #2 and rotate the others in after a few weeks. My current fb picture is of my cat, but it's also been of me alone, me with friends, me with the Mister, and of my feet. Hee!
They're all great pictures. As a photograph I like 1 best, you goth look gorgeous, but I have to say I find all the profile pictures which include someone other than the person profiled just a little strange. 2 is great too and I think will work best, it just looks like it could be cropped a little (though that is very arty and in). If it was me I'd use 3, but that's because I don't like putting my face up there on public websites and because I think pictures of feet are always cool. 4 is a cute shot but you're hiding in the background and I agree with whoever said it might not shrink so well.