A couple of years ago I bought a 1999 BMW 528i for about $4,500, which was about $400 more than it was really worth (long story as to why I paid that much). I love that car and plan to keep it a long time. I'm told that it was the best generation of BMW. After 2003 or so, they started getting more complicated, less reliable, and less interesting, IMHO.

So, for your budget, I say you should be looking at a 1997 to 2003 BMW. Keep some money stashed away for repairs because they are not economy cars. The build quality, though is outstanding.