An important decision

[Sky King]

Good decision, I am the same height as you and I ride at least a 52cm. So It sounds like you need to keep you racks, etc so you can commute, but you could look at different tires and perhaps a different wheel set to get a bit more speed out of the current bike.
A nice supple, folding tire can really boost your rolling speed. Here's a blog post w/ several links about tires, size and speed that may be helpful.

[Crankin]

I am not sure why you think you have to have a double for a bike to be a real road bike. Do you mean a traditional double (I really don't know anyone with one of these, unless they are racing or very young) or a compact double? I have one road bike bike with a compact double and another road bike with a triple. There's very little difference between the two.

[Melalvai]

I don't have to have a double. I just wanted one for the bike that would have been my road bike.

I don't think I'm going to get a road bike. I don't want more speed out of my current bike. It's set up perfectly for what I use it for. The only thing I can't do is a few rides, and there are plenty of other rides I can do. I just thought it would be fun to do those faster rides with a slightly different crowd. But I'm busy enough with fun stuff, I don't really need it.