I was in your shoes a year ago. I was looking at '06-'08 325,328 and 330's with sport & premium packages and a manual gearbox. I love the 330 especially the style 162 wheels on the ZSP equipped cars. Natural aspiration was what I wanted because of maintenance and fuel costs since I drive 25-30K a year. I also plan to keep the car until it's got 250-300K miles on it.
Here's what I did...I bought a 2008 328i with a manual gearbox and 96K miles on July 4th last year. It's white on tan, premium package only. Because of the mileage, I think I got a pretty good deal. It was originally a BMW employee "Brass Hat" car, then sold to it's only other owner. He took very good care of it and had driven it mostly on a long commute up and down the 5 from So. Orange County to San Diego. I had it inspected by a mechanic who gave it the thumbs up, except for the front rotors that were getting near replacement time. Since then, I've driven it 11K miles and performed the following:
Oil change at 98K
Oil change at 104K
Manual gearbox and rear differential fluid changes @ 102K
Replaced fog lamp bulb and one high beam bulb
I initially said I "must have" the sport package, but this car was in such nice condition despite it's mileage and had the other things I wanted more (manual gearbox, premium pkg). I quite like the non-sport wheels on the 2008 car (style 268) vs those on the '06-07. I think the rear offset is ever so slightly different which makes the car look less tippy-toed. Also, the 16" tires are much cheaper to replace, so you can enjoy the car a little more "guilt free" if you know what I mean. For a long distance commuter/road tripper this car is perfection. The engine is magic, so strong and flexible, it just thrills. I tell people that the normally aspirated 3 series is maybe the best all-round car at any price. It's no longer an option now...
With any of those cars, you'll be happy. I think for an automatic, you might want to stick with a 330i though as it has a ZF transmission instead of the GM slushbox that so many folks dislike.
2008 328i 6-spd manual
2003 Audi TT Coupe 225