the aero theme and other effects are the only places i can see feasible effect on the overall performance. any graphical elements added on top of what is considered minimum will make the system work harder and decrease performance. and i checked other effects because of how Vista deals with RAM. it's not like XP where you can throw, in some versions, up to 128gigs on it and have it running lickity split. it decides to be pissy about as little as 4 gigs.
that for me is the biggest strike against vista. the way it deals with RAM.