Spider-man
Flying Dutchman's Sock
I noticed that there was a slight difference in voice for Spongebob in season 4. While S 1-3 it wasn't that high, in S 5-9 it seems a bit more high pitched, S 4 sounds a little... different. I'm not sure what it is. Watch this episode if you're wondering what I mean:
http://www.nick.com/videos/clip/spongebob-squarepants-069-full-episode.html
http://www.nick.com/videos/clip/spongebob-squarepants-069-full-episode.html