With respects to AWD or not, lots of good valid info from everyone in this thread. To help you in your buying decision try this approach:
1. Wait for a decent snow fall
2. Visit dealer and ask for a test drive in AWD and RWD.
However it is unlikely the dealer won't have Snows on the RWD cars. But, it would give you a general idea of the performance in winter conditions. Also another factor might be where you live in GTA(EG. north of the snow belt line) and your daily commuting needs.
I can say that I've driven my sister's 323i (06) and Brother's 335i(08) in snow in the past(both have snow tires). They drove fine in the city in most cases.
My criteria for buying AWD was not to have to put snow tires on (many would debate this, but opinions are like a$$holes, everyone has one) plus a bit more peace of mind (based on my perspective).
One thing I do notice in AWD for sure is driving off from a stop position is alot quicker than RWD. Keep in mind that snow tires definitely provide better stopping in winter conditions regardless of the car, but that means you need to adjust your driving habits to the conditions of the road.