When my wife's Saab was having some probelms, we initially went to the local Saab dealer, who explained that, among other things, her radiator cap needed to be replaced.
Since that seemed rather silly to me, I took the car to Billy's. Coincidentally, Billy used to work for Saab and repaired the various problems for a lot less money. He also declared the radiator cap to be in good working order (not surprisingly).
Since ten, I have always gone to Billy for everything from car inspections to tune-ups, oil changes and more serious car problems. He is very knowlegable, extremely friendly and doesn't mind taking a few minutes to look at a problem if I just happen to drive by with a question.
His success may be getting to be too much -- it often takes a few days to get scheduled for my oil change, but as long a s I plan ahead -- I'd rather go to him than to a national chain and have them try to sell me various additives and such that I don't really need.