Buying a synthesizer?

Alrighty well i'm looking into getting a synthesizer. i've been a playing music for basically my whole life (mostly guitar and drums) and now i think im gonna give synth a shot. Im looking at the newer and the older models of the microkorg, the KM and XL. now i've never played anything with keys before so is there something that makes on synth better than the other? also is there any other things i should buy to get the most out of my synth? thanks!