I change the oil on my bike, but I take my cars elsewhere. I went to a Jiffy Lube in LA once and didn't like the feel, but I've found a great place here in Oregon. It's a Texaco Xpresslube, and here's where I like 'em:
1. They have a checklist that they go over loudly as they're doing the work. I stay with the car, so I can see everything they do under the hood, the only stuff I don't see is what they do in the bay beneath. When they start, they get a laminated sheet and wipe it clean, then each fluid they check, they dab it into the appropriate box on the sheet. When they're done, they show me the sheet so I can see the color of each and what shape each is in. The only thing they've ever suggestive-sold me on was the air filter, and that wasn't based on mileage, they pulled it and showed me the dirt.
I've watched 'em work, checked the fluids on my own after getting out the shop to see if they were ok (it's my butt if a component fails, trust but verify like when pre-flighting), and I'm satisfied that they're a good shop.
If you don't do your own oil, look for a good shop. The good shop might be one of the chains or it might be the local guy, but when you find it, vote with your dollars and go back.