^ tim has most of it right. you want to get the maintenance items done, and all of that stuff he mentioned is less than $100 really (except the clutch).

also do the fuel filter as well.
spark plugs
air filter (obviously)

and you might want to check over the coolant hoses and vacuum lines, especially inside the intake runners and in hard to reach areas, will make things alot nicer when you don't have to crawl your hands in there later on.

and if you do the clutch, definitely do the pilot bushing, throwout bearing, fork pivot, and probably a new clutch slave (i'd opt for a stainless clutch line since it's only like $20). just some stuff you won't have to bother with later.

oh and engine mounts if yours are bad. thats one thing i would get out of the way.