I don't consider myself a huge BMW fan anymore (I loved the E28 and old 6/8-series), but I drove my friend's 2001 BMW 540i today (E39), and that's gotta be one of the best sedans I've ever tried. It actually drove much nicer than the newest 5-series. Awesome compromise... E39 was comfortable like big Peugeot's and Citroens but also sporty and "rough" like the sports cars. Much nicer than my company Mercedes E200 without a doubt.
It's a great car and definitely affordable. And despite being 10 years old, it was very modern but still had the old BMW "spirit".
I actually fell in love with this car... maybe I'll buy one for my wife.
PS: Not my friend's car in the picture but it looked like this one.