1. s5 - i really got into the plot arc of this one, loved that the baddie was another superpowered female who actually scared Buffy; Spike has great starring eps in this one and I love watching him gradually fall for Buffy and jon the scoobies; Dawn was surprisingly good and fit in, loved where her story went(bit like Halo's in Batman and the Outsiders I thought later on).
It was just very good quality throughout for me, it peaked here.
3. s2 - Became a big buffy fan with this one, it set the standard for what these kind of shows should be like. First time I ever felt like I was getting a regular superhero comic delivered straight to my tv, having a brilliant sh live action show with a continuing story arc was something I'd never experienced before this series, amazing.
5. s7 - Someone on the thread said this one started off well but nosedived whe the potentials were introduced, I have to agree, too much time spent on underdeveloped characters and not enough on the stalwarts like Xander who got nothing out of this one except an eyepatch. I have a problem with the uber-vamps falling so easily in the final battle when it took Buffy all of her might to bring one down earlier. But, it has some great eps, a good follow up to Spike's origin ep from s5 and Faith is back(although she was even better over on angel s4).
6. s6 - some real stinkers in this series, my worst ep of all time is 'Doublemeat palace', 'Gone' is pretty rank too for an invisibility ep. But, it has some good things going on in it, i love the 2part opener, the trio are not too bad and have their moments(the ep where they make Buffy think she killed that girl is a great one). Some good Spike too, and at least they tried ahving a depressing 'real world' series here. Problem was, for s7 too, that JW went off to make FF and did not scriptsupervise/re-write on every ep. I think he should've waited til Buffy was done before embarking on his new endeavour, it would've benefitted both of them.
s6 has the best cliffhanger for me by far, could not wait for s7 to see how that turned out.
7. s1 - Good pilot that laid everything out, easy to understand, followed by hit and miss eps. Hit - the pack; angel; final ep. Miss - that one with the robot thing. I was wondering what the big deal about it was at points, it being touted as the next big thing from the states, it took s2 for me to see why.