Entertainment Weekly's latest issue has a bunch of Top 10 and Top 100 lists for different categories (best TV show, best drama, etc.). Top 10 lists are fun, but they tend to be pretty subjective and not very convincing to those who don't share your tastes. Still, EW ranked Buffy pretty high on several lists, so I thought I'd comment on them.
Buffy rated No. 1 in the science fiction category. This is nice, except that the show wasn't sci-fi by any reasonable definition. I guess they meant fantasy/sci-fi, because they didn't have a fantasy category. The rest of the top 10, though, was sci-fi.
Buffy also rated No. 2 in the category Cult Classics, behind The Wire. It finished No. 3 in the Best Drama category, behind The Wire and The Sopranos.
I never watched The Sopranos (I don't have HBO and never picked up The Sopranos later), but I have seen The Wire and liked it a lot so I thought I'd explain why I think Buffy was the better show.
First, the best episodes of The Wire don't match up to the best of Buffy. The Wire was more consistently written -- no episode of that show is even close to as bad as, say, I Robot, You Jane. But Buffy hits peaks in episodes like Passion, The Body, and OMWF that The Wire can't match. I'm a big believer that peak performance counts for a lot (see my discussion of Mozart in the Introduction), so Buffy gets the nod.
Second, Buffy ran far longer than The Wire. The Wire only had about 50 episodes total, while Buffy had 144. This is important: most shows decline over time, and The Wire is so consistent in part because it never went through that phase (and at that, S5 wasn't up to the standards of 1-4). If we were to take just the top 40-50 or so episodes of Buffy, the seeming advantage The Wire had in consistency of writing would disappear. Moreover, Buffy then produced an additional (arbitrary) number of very fine episodes above and beyond that. Again, the advantage goes to Buffy.
Third, I can re-watch Buffy almost endlessly (and have). I think The Wire is terrific and liked it enough to watch it three times, but at that point felt I'd gotten all there was to get. I take this to mean that Buffy has layers -- depth, if you will -- that The Wire can't match.
In short, my Top 10 list is objectively better than EW's. :)