I'm starting this build from scratch, so all the drive gear will be different. Its a first for me; I've got everything except for the drive system (cranks/gears/shifters) so learning and using my wits as best as possible! Starting with the correct shifters then getting the right mechs (not got onto this yet...!)
My rear wheel actually came with a used Miche 9 speed cassette, but I'm not sure as to how worn it is. I was assuming I'd have to replace it. Not sure if its a campag or shimano fitting - does it matter which brand a cassette is as long as its the right number of cogs?
What brand is the rear hub? You could always try a new chain on the old cassette and see if it works? What make is your old chain?
AFAIK Miche cassettes are Campgnolo fitting (correct me someone!?) so you'd be looking for Campy Ergo shifters to make this work at the back, I think Ergos have friction up front though, so pretty much any front mech could be made to work (ideally with a cage to match the shape of the largest ring). There are threads on CRC forums about 'Shimergo' but that's a whole new kettle of peas.
If the Miche is actually Shimano fit, SRAM and Shimano cassettes are generally interchangeable.
Some good reading here:
(the 'Compatibility Among Brands' bit)
EDIT, quick way to check your cassette is whip it off and try it on one of your Shimano 8/9 speed hubs. If you can't get it off with usual Shimano lockring tool then it's bound to be Campy!?