Welcome to BF and good luck with your conditioning goals. Cycling can play a big role. A wrench in my lbs lost over a hundred pounds commuting 20 miles rt to work.

Take what boomhauer said to heart. And the bank. Look at the Trek FX 7.1, 7.2, 7.3 series for a quality, hybrid type bike. For a tour bike that can also be your commuter, check out the Windsor Tourist. More like a road bike.

Fit is First. Get that right for sure. Check out your local bike shops for help in that area. Buy as close as possible than tweak it to just right as you put on the miles. Tweaks usually involve saddle type, saddle position, and bar height/type. The more hand positions, the better. Get radical and consider aerobars for riding comfort and battling headwinds and hills.

Don't put off by all the confusing advice you'll get. Bit of truth in it all. You'll finally sort out what works for you. Do your best to get it right up front to minimize cost. Not that easy sometimes.