Well, like everything else in this business, it depends. I will break down what I am looking for in cymbals for the situations that I perform in most regularly:
My Reggae band: Simple set up of a set of hats and 2 crashes, no ride. The hats need to have a nice articulation and an open sound that's a bit on the bright side. For this I use an old set of Zildjian New Beats, but inverted so the heavier bottom cymbal is on the top. This gives me a nice stick sound and a musical, but not overpowering open sound. For my crashes, I want something that opens up quickly, but isn't so light that it is too dark. I am using an A Custom 17" crash that's about 7 years old. The A Custom's were a little thinner then and I prefer it over the current line. I also use a 16" Armand series Med Thin crash. They both open up quickly, with the Armand decaying quicker than the A Custom, but the bell on the Custom is beautiful for tiny, quick accents.
My Jazz trio, Bass, Drums, Guitar: Very different setting from the Reggae band and requiring much different tones. For hats, I switch between the old New Beats, top cymbal on top, and a set of Sabian Light Hats (925g top, 1083g bottom). The later have a very nice warm tone and a nice chick with the foot, cutting but musical. I'm currently using 2 crash/ride type cymbals, but I'm in the market for a third. On my left I use a 19" K Med Thin Crash that is about 7 years old. It's light enough that it gives me a lot of tonal options on my left. I often drape a chain on it for a nice sizzle. My main ride is a 22" Dream Bliss, 2395g. This cymbal has a nice woody stick that sits on a nice dark wash. This is brand new cymbal and I have yet to determine all of the tones I can get from it. It's got quite a few sweet spots. I have really laid into this cymbal and not once has it gotten out of control. It has a big, dark crash and a killer edge wobble, taboot. I am currently in the market for a flat ride to add to this set up. Probably a 20" that has some dark tones and a ton of stick. These types of cymbals tend to be quieter in nature, so I may consider popping a couple of rivets in it for some more presence, but I'm just not sure. I'm still doing some research. I'll let you know what I've decided on in the next few months.
For the studio, I also have a couple of old Sabian splashes from the 90's, a 10" AA and an 8" AAX. Very musical splashes and great for accents in the studio. I think I've got a Zil Bel lying around somewhere too, but haven't used it in quite a while.
I've owned and used a bunch of other cymbals as well, but for my current situations, these are the cymbals I usually go with. I use a combination of them in a bluegrass, blues, acoustic rock band I play with on occasion. I hope this helps. Thanks.