My cymbals are mostly Paiste, but I do occasionally switch out for something non-Paiste.
Ride: 20" Paiste Prototype, or 22" Paiste 2002 Power Ride
Hi-Hats: 13" Paiste Sig. Dark Crisp (non-Paiste sub: 1970s 14" A Zildjian New Beats)
Crashes: 16" Paiste Traditional, 17" Paiste Dark Energy (non-Paiste sub: 16" A Zildjian medium-thin crash)
Effects cymbals: 18" Paiste Dimensions thin china; 8" K Zildjian splash
I don't have any specific loyalty to the Paiste name - I just like the sound of their cymbals. Let's put it this way: when I go cymbal shopping, my search usually begins and ends at the Paiste display, but I do check out other brands of cymbals as well.
I actually mix brands in other aspects of my equipment as well. Forget about hardware - that's a mix all over the place, as I pick up a stand here and there. I've got Ludwig drums, but my 10" tom is a Pearl Export.
And snare drums...that's a whole other matter, with brands all over the map.
