Get a Toyota, the Camry is one of the most reliable cars. Or even a Lexus.
German cars require more maintenance and the maintenance is more than a Toyota. The dealer is a big rip off, they will just overcharge you, this may have to do with the current economy and or due to their high overhead.
You need to change your oil every 5k, you can DIY or go somewhere cheaper.
BMW and Mercedes are good, but expensive to maintain. You need to change oil every 5k regardless of what they say. Air filter ever 30k (usually easy to do), trans fluid/diff fluid ever 30k, spark plugs (30k- or 45k or 60k or 120k depends)
Those are the basics all cars need and you can stay away from the dealer for a long time.
Get tires from Tire rack and ship it to their certified installer. cheaper.
Generally speaking BMW, Mercedes, are more reliable better built. Porsche is a diff level, but stay away from VW and Audi.
Stay the hell away from Jaguar, Land Rover, Range Rover, english cars, etc. They seem to have more issues than a lot of BMW, Mercedes.
Cant comment on the Fiat. But I would stay away from it.