Desmotourer,
I got the Ducati hard bags (panniers) for my '03 Monster 620. They were kinda expensive, but less than I expected. I didn't get the top case, though. They work well and have a good amount of space; either one will hold a full face helmet. I ride the bike nearly every day to work and got tired of using a back pack. The hard bags work much better. I couldn't find mounts for the Givi bags. Good luck.
Eddie