REC is a great zombie movie but not the best. I'd put Shaun of the Dead above it, and 28 Days Later; maybe Pontypool, I need to rewatch that one...
As for things you haven't seen, you should definitely check out Cemetery Man, Fido, and the Night of the Living Dead remake. You might count the Re-Animator series, and Wild Zero for a ridiculous Japanese zombie rock'n'roll movie. And I haven't seen Colin, but I think it's on Netflix Instant right now, sooo... might check that out, I guess?
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"What I like to drink most is wine that belongs to others." - Diogenes the Cynic