Well, that's exactly what I have: a 1989 325is and a 2008 Z4 3.0si Coupe. Both are light, responsive, great brakes, great engine sound.
My favorite is my Z4 M Coupe. It's fun to drive, but it's also a work of art inside and out. I can literally sit and admire it. I've had a lot of people of artistic bent approach me about the car - an architect once stopped me in a parking garage to do a walk around, while his young assitant looked on with a "what? I don't get it, it's a car" expression. The Z4MC and the E60s really show what flame-surfacing was meant to achieve, especially at night prowling city streets; they're really made to have light play over their surfaces while moving. My 2nd favorite would be the E92 3-series - it's simply a beautiful, elegant shape; oddly I don't like the E92 M3 as much, the sideskirts and hood bulge detract from it. My favorite vintage BMW is the 2800CS/3.0CS; my 2nd favorite is 2002, as just an awesome piece of industrial design. I wish I could daily drive either without Chicago's salted roads eating them alive.
#1, the neo-classics: e38, e39, e46 #2, the future: e85 (roadster) [I am clearly biased here] I think the recent (past 5 years) designs are a bit goofy. Maybe over time they will play out differently. I do like the latest designs, getting back to the roots of BMW. taut, muscular, understatement.
e46 M3 coupe > e46 ZHP Sorry guys but the e46 M3 coupe puts to shame the look of a ZHP/S54 concept, as you're cooking it up.... IMHO of course