I've been driving on Yokohama AVID ENVigor's (All Seasons) that came with the car when I purchased it. Drove the car through last winter (which was extremely mild in terms of snow fall) and on cold roads it was fine. I didn't take the car out on snow covered roads (mostly because I was afraid of getting stuck behind a salt truck blasting my front end) so I can't attest to what the tires were like on snow/slick surfaces. This summer (and last summer) the tires have performed well too.
I don't track/autocross the car. If anything the most "spirited" driving I do is when merging on a highway. Otherwise it's either stop and go in the city (rare since I usually avoid going through downtown with the BMW) or just highway/commuter miles to work.
I've been wanting to get a set of wheels with summer performance tires on them, but I don't know if my wallet can handle it since I have a brake service I need to do plus VANOS at some point soon.