I have one
built into my MicroKorg. I love that little thing.
(theSHALROTH Shamble bobble dimble dooble, Sat 10 May 2008, 17:46, archived)

[nice...
..the one I was using is friend's KorgR3]
(DrZaarlon Is Not As Cool As He'd Like., Sat 10 May 2008, 18:02, archived)

I'm saving up...
...for a Korg MS-2000 (or 2000B), it's a MicroKorg on speed. The MicroKorg has been around since 2002 and it's still being made, without any changes to it (other than a limited edition with Black keys)

I also have an analogue Roland Juno 6 and a Roland MC-303 which is a bit weak, honestly, digital low-pass filters just don't work, but it's a nice little scratchpad and has a useful sequencer.
(theSHALROTH Shamble bobble dimble dooble, Sat 10 May 2008, 18:54, archived)