Probably need a LITTLE more information for a good recommendation, Christian...

What do you intend to do with the keyboard? Are you going to drive some modules, or VSTi's? Do you want to control another keyboard you already have? Do you want the keyboard to be able to control other modules AND operate as an arranger too? Do you want the controller to have it's own sounds? What kind of music are you likely to want to play?

Oh, and how much do you consider a 'good' price?