Spike as a villain was great, partly because he was swearing his ass off with English slang and getting away with it on prime-time US TV. And he was just a sarky bastard, even when he should have known better. Great lines.
"It's a big rock. I can't wait to tell all my friends. Bet they don't have rocks this big."
Wilkins was creepy, and very well done too. The rest...meh. It doesn't help that every single character was shafted in various ways from the third season onwards, and it got worse as the seasons wore on. Season 5 was the last one I watched, and I am very, very glad that I stopped where I did.
Well...I watched Dirty Girls for the Xander scene. That was pretty nasty.