I said Buffy by a fraction in the poll, but that isn't to say I don't love Angel - as with many people, my affections have switched more and more towards the latter as I've got older. Angel's fifth season and Buffy's third are together the strongest years of TV Mutant Enemy have ever produced, imho.
I would have added both but I wanted to challenge myself and others by having to make a hard decission. Buffy is my favorite show of all time but Angel ranks around my 3rd-4th favorite show of all time.