Well if you just want it as a squencer then the 2000 will be fine... Ther is plenty of good quality Sequencer software available, and MIDI boxes are dirt cheap.
As a sample box... well I would suggest a toccata or Delfina-Flipper...
um.. audiolabs (I think that's the name) seem to have a great peice of kit with their software.
I personally like to use my A1200 (on native/paula audio) and MIDI at the same time using OcataMED sounds studio. That is a great machine for reliability putting ideas together... but I would have to say my PC is far more use in the studio nowadays... Simply due to the quantity of software and extreme perfomance avaiable. Despite Windows is a pain in the arse, no Windows 2000 isn't perfect... :-(
