My most recent car was a '07 328xiTouring that I took in a trade-down from my '09 M3 Sedan. I knew the new X3 was coming, so traded my M3 last Sept and drove the Touring thru the winter. The Touring was not big enough for my needs, thus wasn't a long-term keeper.
The M3 was sort of a "bucket list" thing; and I really enjoyed it. Had it just over a year, but was not practical in the longer term. Glad I did it - a truly awesome car with the 4L V8...
I am really enjoying the new X3. It is a great mix of fun to drive, and practicality. I am glad I got the 35i MSport as it makes my giving up the M3 a bit easier to take.