I'm using the included Sigma Photo Pro 3 software to handle the editing of RAW images from my Sigma DP2 Camera. It's actually pretty easy to use and the editing options are straight forward.
My only complaint is that it crashes every time I close it. I'm on Vista Ultimate 32bit and you would think that it's a common operating system to use the software with. I'll probably just reinstall it later on and see if that fixes the problem.
I purposely snapped a picture in a dim hallway here at work to see if I could save the picture with some post editing...I think I did a fair job :)
Here's a before and after shot of my buddy Lauren.
I'm also using Photoshop CS4 (with the new RAW pack plugin...can't remember the name, but I'll post more on it later).