I don't think driving it every day plus 30 mile trips would constitute not enough. It is unacceptable to expect BMW customers would need to drive their cars 200 miles a week for the battery to stay a live.

There are several reasons which have been discussed that causes a high battery drain. If you keep your car unlocked, I do believe there are some things which may be on standby and cause a higher drain. Also, if you have comfort access and the key is kept close, there may be issues as well.

Personally, I have driven my 2008 x5 about 10 miles the past 3 weeks maybe 100 miles in 2 months, leaving it parked for 2 weeks straight regularly. I started it up today a bit worried but had no issues. I always make sure I lock it and I even take the measure of removing the navigation DVD when I know it will be parked for a while since I believe it continues spinning even when the car is parked and locked.