I have a ~3 mile round trip to work. On the way to work its about 1 mile, way home 2 miles (theres a long loop around my work). I did this drive for 2+ years in my 07 335i, no issues. The battery went bad right before my 4yr/50k ran up (at around 38k miles) but 4 years in FL is not out of the norm to kill the battery. I always made sure to take a nice trip on weekends and let it see some highway though.
Currently Drive: 2011 S4 Prestige, Quartz Gray, Black Alcantara, Adv key, B&O, NAV + rear sensors, 19's, Carbon Fiber Trim, iPod...
Previously drove:2007 335i Coupe, Titanium Silver Metallic,Black Leather, Gray Poplar trim, Premium package, Cold weather package, Sports package, i-Drive, Rear sensors, iPod.
Previously drove: 1998 3000GT Vr-4 Red/Black TT AWD AWS