On the Treo's I've always been a huge fan of Quicknews. Since moving back to Windows mobile I needed to find a RSS reader that didn't throw ads at me, slow my phone down, or make me crazy insane with slow download speeds.
The program I ended up with (and registered) was News Break by Iliumsoft.
As you can see it looks a lot like Quicknews for the Palm platform, and supports auto updating, and is able to download the channels at a speed you hardly notice! The closest other RSS reader was slow as molasses and didn't support auto updating.
If your on a Windows Mobile device and want a great RSS reader at a reasonable price you can't go wrong with News Break! Check them out with the link above!