So I've been using the Adobe Lightroom beta for a couple of weeks now and I really like it. It's shaping up to be a very nice application and it's clear that the designers have put a lot of thought into managing a workflow that involves a lot of photographs.
I was using Raw Shooter Premium (RSP) to process my RAW files but I've made the switch completely to Lightroom even though it is still in beta. For one, RSP isn't being updated anymore. It was acquired by Adobe and they've promised RSP users a free upgrade to Lightroom 1.0 when it becomes available. Second, even now it provides a lot more fine-grained control over image adjustment than RSP does. The Develop panel looks like a 747 cockpit. But importantly, every one of those controls does something meaningful and there are no less than two basic adjustment panels you can use instead. Plus you can save as many presets as you like.
It's certainly slower than RSP. You'll need a semi-modern machine to run it properly. But if your computer has the horsepower, Lightroom is a lot of fun to use.
One of my favorite things about it though is that it consolidates my workflow for RAW and JPG files. Lightroom provides the same UI for management and development regardless of the file type. I shoot a lot of RAW images but I shoot a lot more JPG. Now I don't have to have two separate workflows for dealing with those files.
I recommend trying it out if you haven't already.