Then again, if you want luxury, just buy a US-made luxury truck or SUV. A used Escalade, Hummer, Denali, Suburban, or Tahoe can all be had for rather cheap....and they all share parts and are relatively easy and cheap to maintain. If gas is your concern, than you shouldn't even be in the market for something like a BMW anyway.
If you want straight-line performance(the ONLY kind of performance because wanting something good for twisties makes no fuckin sense here in the states) than you buy an American car like a SRT8 300C or Charger. These motors, along with Ford's new 5.0 and GM's LSX series can easily put out well over 600WHP with not a ton of modifications. High-dollar Euro cars get raped at the track and on the highway all night long.
If you just want a car that'll last as long as possible while giving you some sort of comfortable luxury, than just buy a newer Toyota Camry. Or, if you are feeling very old, a Lincoln Town Car. The Lincoln, along with its brothers the Grand Marquis and the Crown Vic, are the last car ever made with a body on frame build. There is a reason why the Panther platform serve as police cars and in the livery service....they last longer than anything else and can get the shit kicked out of 'em.
In terms of performance, price, and reliability, none of the big Euro cars are near the top. If you like to spend a lot of money at the dealership, push a lot of different buttons that you have no need of whatsover, ride in a car that feels like a plushy couch at high speeds(ok, that does feel cool), attempt to impress people you do not know or will ever know, than a BMW, Mercedes, or Audi is for you.
DISCLAIMER: I came damned close to buying a BMW 530i....the ride and interior are a cut above everything else. I do see the appeal, though.