Having a Triton proX, a k2661, a k2500r, a Motif Rack ES, a Virus B and a V-Synth XT I could seem a little like someone who just like to collect synth... anyway, no, this isn't my case. Here is how I use them all:
1 The Triton was the first piece of gear of my studio, I used it live and to play in my studio. I don't use it live anymore since it's too heavy and due to the fact I don't play in a band where I need 88 keys anymore. If I'll join a band where I'll need all the 88 keys maybe I'll use it again for live purpouse, till now it will remain the center of my studio since I play piano too and I really need an 88 with hammer action.
2 K2661 I use it as my main keyb in live situation due to its incredible sound and master capabilities, can't live anymore without it.
3 Motif Rack ES: I bought it a year ago to play live with a master+rack setup and I still use it in live situation (now I'm waiting for a guitarist to join the band cos we kicked out the old guitarist) with a metal cover band (I use it with the kurzweil or with a CME UF7). I use it in my studio for acoutsic sounds too like basses some flutes, guitars, drums etc.
4 Virus B and V-Synth XT: it's the center of my setup in a prog-psychedelic band I play, it's the perfect companion for the K2661 and the new V-Synth XT I bought, I need many strange sounds, samples etc with them so Virus and V-Synth XT mastered by the K2661 are THE perfect setup for the band. They are also really usefull in studio.
5 K2500r I bought it for a few money a few years ago, then I tried to sell it but the same days it had trouble with scsi and ram... so it can't work like a sampler anymore... I couldn't sell it in that condition and I decide to keep it in my studio for its VAST capabilities to create strange synth sounds and noise.
two more things to say: when I talk about "studio" I don't mean a real production process, I just experiment for myself to find something usefull for my bands, live and for me too, just for pleasure. The second is that I love all my synths as the first day I had them and I really think that this is my perfect setup... untill GAS will rule again on my brain and make me spend some more money on something analog that I really would like to have here with me
regards, Lorenzo