My '95 540i (an E34 chassis) has 270,000 miles on it -- 190,000 under my ownership. The transmission shifts smoothly and the engine consumes no oil between 10,000 mile change intervals. The car has gotten a new water pump every 80,000 miles and a new radiator at 200K. If I make it to 300k (and it seems that I could if I want to hang onto the car) I'll probably treat it to another radiator.
The engine required some new intake and cooling system gaskets around 215K (the infamous "valley pan" job). I replaced them in an afternoon. Edit: Oh, and I rebuilt the transmission valve body around 150,000. Kinda fun, actually.
Control arm bushings are a wear item, particularly the uppers. The SOP is to replace the entire control arm. The lower control arms on my car lasted 175,000 miles before they were worn out. The uppers may last 100K with luck.
Yes, it's required some repairs. But I paid $9k for it in 2005, and for that money vs the mileage it's seen, I'd say it owes me nothing at this point. This was my road warrior on a 90-mile round-trip commute from 2005 through half of 2013.
Orangehairfella, I've owned an E30 as well. To me it's the best 3 series model, although I haven't owned an earlier E21. Yes, it needed attention, and I never got the AC to run right. That said, my car was a cabriolet, so I didn't care much about air. The car's biggest weak spot was the timing belt ... what were they thinking? Every other BMW engine has had a chain. And again, control arms are a wear item.
The E30 took me to work in fair weather from 1997 to 2002. The foul-weather ride was an '87 Audi 4000cs quattro. (Wanna talk money pit?)
BTW, I just picked up another E34 BMW -- this one's a 1995 525i wagon with 190,000 miles. Got it for $2500, with a manual transmission conversion kit and manual driveshaft thrown in. It needs a little work, but hey, I'm retired. I figure it's good for another 100K miles.
The key to this approach to motoring is to have a backup car in the wings. You don't want to be in a position where you HAVE to fix something today, or tonight. I remember changing exhausts on a 5-year-old Ford at 3 a.m. so I could drive it to work the next afternoon (I worked second shift). And it seemed like every other bolt on that Ford was rusted solid. In 20 years I can count the number of broken BMW bolts I've seen on one hand.
Bruceski, if you're looking for a vintage German that is a nice weekender, you might consider a WELL-KEPT early-mid 80s Mercedes Benz turbodiesel (W123 chassis). The engine management is totally mechanical, and the diesel engine is just fun. They're a bit messy (oil drips), though. Fuel mileage is in the mid-20s and the seats, when they're right, are incredibly comfortable. There is a big cult following for these cars -- in part because you can run them (to their detriment) on french-fry grease.
I drove an '82 300D coupe to work from 2002 to 2003, when it got rear-ended on the freeway. I replaced it with a rusty 300TD wagon that I finally took out of service around 2011.
The R107 roadsters from the period are also nice, but thirsty. If you want any power to go along with that sleek look, you'll pay for it at the gas pump.
The W126 Mercedes-Benz coupes are a work of art, but again they aren't gas misers. Again, a very nice vintage toy.
I am a real fan of the E34 BMW 5 series (1988-1995) but I'd take a chance on the later E39 chassis (1996-2003). Every used BMW I buy gets an overall inspection by a third-party mechanic before I part with any cash.