Of course, love doesn't conquer all. We know that in real life, and Buffy and Angel learn it themselves -- the hard way. The emotional punch of this relationship is that we learn it again, painfully and violently, right along with them.
*sniff* I'm another who shipped B/A originally, years ago before I discovered fandom (and slash, heh) or knew what a shipper was. I've said that I'm not really a B/A 'shipper anymore, but that's just not true. I'll always love it because of the tragedy, the epic nature, the . . . gah, the pure emotion. No matter how I feel about other ships involving either character (and there are other ships that I love) I will never be able to watch 'Becoming' or IWRY without tearing up. Excellently, excellently written.