Go to the local shop you like that treats you like a valued friend. Don't be afraid to ride a carbon frame bike. You might have to invest in a back wheel that is a little heavier duty (I know I did). Talk to the shop about fitting the bike to you which is more than just raising the seat to the proper level (it also can include replacing the handlebar stem to one with a different angle to make the bike more comfortable for you).

There are many good brands out there, and many good bikes.

MOST IMPORTANT is get the bike that YOU will want to ride; getting a bike that you won't want to ride means you just bought an expensive cloths rack.

Join Strava.com (free) to track your efforts, and riders like me would gladly follow you to give you encouragement (not to compete).

Set a weekly goal even if it is only five miles a week and then meet that goal (you can always make the goal bigger later).

And when you ride have fun.