I second the K2000 recommendation, especially if you're attracted to sampling; the add-on package for the 2000 and the K2VX series proper are, um, righteous. Its a scary serious machine.
However, if you choose to stay in the Korg realm, I'd say pass on the T series and head for the 01/W, especially the steroid-enhanced fd model, which has a MUCH better sequencer, 32 voices as opposed to 16 and has caught on in such a way that you can locate SQUILLIONS of patches on the Net. FYI to everyone-you can find a mass of these little beauties at korg01w-list@vienxu.com in a couple of different formats.
The Ts ARE good synths, but if you're going in that direction, go for the muscle! The few extra bucks an 01 will require will be well-spent. The Trinity is also a dynamite bet, presuming you can handle the weird touch-screen for programming it. I have massive fingers that don't LIKE that sucker, but it IS a lively, worthwhile instrument. A little brighter than the 01s in a sense, perhaps, but as always, that's just MY opinion. Check it out for yerself. Hope this helps.