My first rec automatically goes to Kristi (bashipforever; same on ff.net). She was not the first B/A author I read, but she was the first good one. And she's really good. What I think I really like about her writing is that we are on the same wavelength B/A-wise and ficwise. The former might be because her fic influenced my views (a lot of good writing does that; I won't say all because I'm uncomfortable with all-encompassing statements like that) and the latter is because we both enjoy a good dose of angst, but in the end, we love the happy ending. All her fic is amazing and I have read it all at least three times (correction: I have read all her B/A at least three times. Luckily for me, she has a lot. :D) but here are some of my faves (in no particular order):
The 3 I can't read without bawling (seriously, every time!):
1. Full Circle- http://www.stumbleintograce.com/Kristi/fullcircle.asp
2. Scar Tissue- http://www.stumbleintograce.com/Kristi/scartissue.asp
3. The Burdens We Bear- http://www.stumbleintograce.com/Kristi/burdens.asp
And an extra angster for good luck:
4. Cruelty- http://www.stumbleintograce.com/Kristi/cruelty.asp

The epics:
1. Stumble into Grace- http://www.stumbleintograce.com/Kristi/stumble.asp
2. Fallen Angels- http://www.stumbleintograce.com/Kristi/fallenangels.asp
3. Beautiful Disaster- http://www.stumbleintograce.com/Kristi/beautifuldisaster.asp

Cute/Funny/Happy/Fluff/All of the above:
1. Things to do in Sunnydale when you're chipped- http://www.stumbleintograce.com/Kristi/chipped.asp
2. Beloved- http://www.stumbleintograce.com/Kristi/beloved.asp
3. A Series of Fortunate Accidents- http://www.stumbleintograce.com/Kristi/puppetangel.asp

General yay AKA the Happy Ending:
1. Possession- http://www.stumbleintograce.com/Kristi/possession.asp
2. Three AM- http://www.stumbleintograce.com/Kristi/3am.asp
3. First Christmas- http://www.stumbleintograce.com/Kristi/firstchristmas.asp

Woah, too many recs!!
So, a million huzzahs for Kristi. Check her whole archive out here- www.stumbleintograce.com/btvs.asp.
Happy ficcing!