Get an external MIDI interface, and a normal MIDI keyboard, otherwise you`ll regret it in the long term when u want to expand.
I`m using OctaMED SoundStudio on A4000T, ProMIDI, Casio CTK-601, Akai S3000XL, Performa 5320 (cos i need it`s SCSI for the sampler), A2000 for effects, got a TB-303 on the way (hopefully). Yipeee!!!
Get yer Akai out!! lol