AMIGA & MIDI

[Ral-Clan]

Search for Bars & Pipes on Google.

Probably the best MIDI sequencer ever made for any computer platform.

OctaMED is good, but it's a different beast: more of a sample triggering program (although it can trigger MIDI too).  A bit mechanical in its approach to composing.

Bars & Pipes is for those who think more "organically".

Free and still being updated by Alfred Faust (thank you Alfred!).

http://www.alfred-j-faust.de/download.html#BPNew

[Ral-Clan]

OctaMED SoundStudio v. 1.3c (I think) is the latest free version (available on the MED homepage once you sign up).  I'm not sure if it's the best version for an A500 though, as it is the most CPU/RAM intensive.