I currently have a full array of Sabian AA/AAX:
14" hi hats
10" splash
16" stage crash
18" stage crash
18" chinese
20" studio ride (which I actually use as a crash ride, because it's very clangy when you bash it)
21" raw bell dry ride (this might be my favorite cymbal of all time... it weighs a metric f**kton, but no matter how you hit it it sounds just like a ride cymbal should sound. Plus, the raw bell sounds flat-out amazing).
When I go to the shop to look, Sabian's HH are definitely the cream of their crop, but sadly I am not made of money and can't afford to replace all of my current cymbals.
I like my Sabians because, as somone said above, they're durable. I broke one in college, called Sabian on the phone, and they told me to send it back and that they would replace it. No hassle. That kind of customer service goes a long way.
My cymbals are bright and crisp; I once had another drummer come up after a show and ask me where I got my hi-hats, as if he'd never heard something like them before. They are run-of-the-mill AA hi hats. The Stage Crashes are bright, but firm. You can ride on the 18" for heavy passages and not lose the deep sound from it, and the 16" cuts through.
The weakest of the cymbals that I have is the chinese... it sounds more like a ping (think: Metallica, And Justice For All album china sound) than a good, gong/swashy sound, but I don't use it all that much honestly.
I used to have a 16" crash that was a Sabian AA El Sabor crash, and that thing was simply awesome. It was a bit darker, but the sound was unique and unmistakable. Sadly, it met with an untimely demise.
Overall, I chose Sabian because they were more affordable than Zildjian back in my poor-college days when I started building my arsenal, but I've come to love the cymbals.