Yamaha Motif XS
The Yamaha Motif XS is a synthesizer with 128 voice polyphony, 16 part multi-timbral playback, digital effects processor, arpeggiator, sampler, and 16 track MIDI sequencer. It’s available with an 88-note balanced hammer keyboard, a 76-note FSX keyboard or a 61-note FSX keyboard.

Yamaha MM6 Synth
The MM6 is a 32-voice polyphony synthesizer that uses sounds found in the Yamaha Motif. This keyboard's main feature is it's pattern generator that has a number of different styles and play the backing drums, bass, and other accompaniment instruments.

The Yamaha S90 is an 88-Key Synth with hammer action weighted keys and 64 note polophony. It comes with 640 sounds some of which are from the Motif series. It's designed for simplicity rather than absolute control of every sound parameter. It has 115 MB of 16-bit WAV ROM with 1347 different WAV sounds upon which you can use.

The Rackmount version can save you room in your studio. It offers the same sound engine and features as the Motif ES8 but doesn't have a keyboard.