Most Geico commercials annoy me, in that almost-but-not-quite-funny way that Taco Bell seems to have perfected. But I have to say, I find the Peter Graves ad quite charming.
I also like the one with the movie trailer voiceover guy.
Which in turn reminds me - this may very well be the greatest movie trailer of all time, provided as a public service for those of you who haven't seen it already:
(I wonder how many of these guys there are...)