Tips for bike shopping?

I have not had a bike since I was a teenager (I'm 23 now), and that was a hand-me-down from my sister, so I know nothing about bike shopping.

I'm finally starting to look into getting a bike now, but I'm so lost. Who knew buying a bike could be so intimidating?

I would just use it to ride around the neighborhood, maybe down the street to get something to eat. What type of bike should I get? Brand recommendations? How do I know what size to get? Where can I find the best deals?