"Hmm well I would occasionally require accustic sounds but my biggest passion is music such as Depeche Mode with Alan Wilder "
Then you might want to check out.

The Ion ( 600$/800$ ) or Micron ( 400$ ) from Alesis. I happen to like the interface of the Ion over the Micron...both sound great.

Or the MS2000 ( 700$ ) or MicroKorg ( 400$ ) from, well Korg :P Each have a nice dark grit to them...much like the boards from Alesis I like the MS2000 over the MicroKorg for real time controls.

While these are out and out virtual analog synths...you would be surprised some of the accustic/wind sounds you can get out of them. While you might not get straight up acoustic guitar out of them ( not what their made for )...you could just get a sub 100$ acoustic to meld with them...hahah plus you could run the acoustic guitar through the synths and all their filters/effects and so on.

Beyond that out of the workstations you listed...I would have to say the Triton. It would take care of the acoustic sounds you might need. Plus some peoples subjective gripes of the Triton could work for you...such as its sounds hollow, digital what the hell ever they might say. Plus if the Triton lacks something you need...just add the sampler option to it, problem fixed.