I live in Minneapolis - what you need as much as a new bike is an LBS (local bike shop) where you feel comfortable talking to the sales people and where you'll feel comfortable going back when you have further questions or need adjustments. There are LOTS of great LBS in the Twin Cities, though some focus more on the higher end. I personally frequent The Hub (at their Minnehaha location, but they also have an outlet at Cedar/Riverside) and Freewheel. Both The Hub and Freewheel are coops. Penn Cycle is a local chain that also has good knowledgeable staff. I personally have not that been happy with the folks at Eriks- they've always seemed like they want to be catering to a younger crowd- but YMMV.

The Grand Rounds paved trails around the rivers and lakes go forever here - for the most part, you only end up on crushed limestone if you head out west towards Minnetonka. On the paved trails, you will be fine on a comfort bike but also might enjoy a hybrid or even an entry level steel framed touring road bike. The latter could serve you well now and keep serving you after you get in a little better shape.

Ride a few bikes and pull the trigger soon - it's prime cycling season right now!