My wife drives a Z4 35i. Perhaps not as economical / practical as an F30, but I think we have the best of both worlds with the E89 and F10. I'm biased - I recommend taking a hard look at the Z4. Maybe consider a 2-3 year old if you want to keep the costs in the same ballpark.
Happy car hunting.
2013 535xi, Carbon Black, beige interior, M Sport package, HUD, DDC & ARS
2010 Z4 35i, Crimson Red, beige interior, 6sp manual, Adapative Suspension
2000 528i, Cosmo Black, beige interior, Sport package (retired)