What are my options for selling software independently on Windows?

Question

I am looking to port a tool from the Mac app store over to Windows, the platform where I spend most of my time these days. I've spoken with the author of the original app and we've begun talking about licensing options should I decide to sell the application, and it seems like it would be feasible.

I've never sold software independently, let alone on Windows. That I know of, there is not (yet) an equivalent app store for Windows (maybe one coming with Windows 8).

Assuming my product was done today and I was ready to go to market, what options do I have for selling software for Windows as an independent developer or Micro-ISV? I know can sell it through my own website and accept PayPal, but are there options that will offer more visibility, similar to that of the Apple app stores? Any options to avoid?