considering buying a BMW...

I've never owned a BMW, but I need a good reliable used family car that I can drive for the next several years with two kids in the back. I like the Honda and Toyota products, but frankly they are just boring. The BMW style really appeals to me, but I don't want some exotic car that requires expensive maintenance. I'm interested in knowing more about the long term dependability and expense of owning a BMW. What is the life expectancy of this car? Ideally I'd like to buy one with 80 some thousand miles on it, and drive it for another 100K miles, with minimal maintenance costs (like a Honda or Toyota), but I don't know if that is a reasonable expectation. I just don't have any experience with German cars. With fuel prices what they are, I'm definately leaning toward the 4 or 6 cylinder models (which don't seem as common). Any advice, tips, and cautions are greatly appreciated.

Thanks.