I plan to get fully flamed for this, but I have a list of cars that I will never own because maintenance is ridiculous. Flame away. I just thought if any of you were considering these vehicles... don't.
Mazda 3. Its not so much that they're hard to fix, but they keep breaking. We have 5 at the shop. And I'm not talking about little stuff... one has a broken motor mount after hitting a pothole. It didn't dent the wheel or throw the alignment off... it sacrificed the motor mount. And don't even get me started on how you have to remove the A/C compressor to get the pass side control arm off.
Nissan Xterra. Any car that requires you to remove that much crap to replace valve cover seals that fail every 70k needs to be shot. Plus, the intake you have to remove has two water lines smashed up against the firewall (I just cut them after an hour), and has two electrical connectors UNDER the intake. All of the vacuum and water lines are ATTACHED to the bottom of the intake, so they have to be removed.
Any GM FWD with the quad 4. cracked heads, a water pump that is estimated to take 6.6 hours to replace, but takes 9... you have to remove the intake, exhaust, and motor mount just to get to the water pump.
VW new beetle. I've worked on some older VWs, mostly A2s and never had too much trouble. But replacing the alternator requires draining the coolant, removing the lower rad hose, and then (get this...) removing the entire front bodywork; BOTH fenders and the front bumper. Changing the timing belt is such a chore. I expect to have to remove the upper engine mount, but to have to remove the actual motor bracket on the engine (which is 5" wide in a space 2" wide... not kidding.) Then to get the timing belt on, you have to remove both the tensioner AND the cam sprocket, then jockey them into place while holding the cam on its mark and fishing two bolts into their homes. Then once you get the motor mount back in place (if you didn't break off the cheap bolts getting them out) you have to use new bolts every time since they are torque to yield.
Chrysler concorde/intrepid or any variation thereof. If you've ever tried to replace a transmission in one of those, you already know. Not to mention that the knock sensor is in the valley, and the water pump is behind the timing chain. If you want to replace the knock sensor, it requires tearing the engine down to the shortblock. If your water pump fails, it means your oil becomes coolant soup and fries the bearings really quickly.
VW B5 Passat. ABS modules that fry expensively, non intuitive electronics, and terrible room for maintenance. I have been trying for a week to diagnose a low oil pressure light. The pressure is fine, the sensor is fine. You know what fixed it? Replacing the ABS module. Don't ask. Its a known issue on VW forums. And that throttle body/IAC/TPS unit on the 30v? Fuhgettaboutit. Half the stuff on that car can't be touched without VAG. I can't even remove that throttle body without having VAG to recalibrate it. The suspension is inspired with fantastic geometry, but complicated. The front LCA is two separate arms, each with their own non-servicable ball joint and non-replacable bushing. You can't even lube the ball joints, and the bushings are soft and spongy.
Anyone care to add? Anyone care to disagree?