I would have to go with Buffy all the way! I started watching Angel but somewhere along the line I stopped. I wasn't a huge fan of David Boreanaz's acting in either Buffy or Angel, but I love him now in Bones.
I agree with Highlander II that the Joyce and Spikes scenes were fantastic.
I also really enjoyed the roles that Cordelia and Anya played
I never liked Tara and wasn't sorry to see her go; I thought Kennedy was a huge improvement
One character that I would loved to have seen more before she was killed and replaced with Faith was Kendra (I loved the relationship between her and Buffy)
Can't wait until Joss's next show comes out Dollhouse
