Hi Gary,
I used CS2 + Bridge for a long time, creating my own workflow - which worked for me. After reading about LR I took the plunge with LR2, and now I use LR3 + CS4.
I couldn't be happier. Like others have said LR complements CS - I now use CS only as a pixel editor or where I want to work in layers; LR is a workflow tool with a powerful development module, which I find more intuitive and easier to use than CS4. As a bonus its image database ("library") functionality is very useful if you have large numbers of image files.
LR has given me a faster workflow and better UI. I spend most of my time in LR and leave the pixel finessing to CS4. The two products are designed to work together that way, and I found it easy once I understood it. If you download the trial version, LR has a tutorial built in, which explains the concept and use of the program very well. It just doesn't go into a lot of detail - see next para:
I recently attended a printing demo at an imaging show and was surprised to learn that I wasn't using anything like the full potential of LR's development, pixel editing and local adjustment capabilities. I saw local adjustments being done that I'd always assumed were better and more efficiently done in CS4. Not necessarily the case!
Its other modules (Slideshow, Print, Web) are intuitive and easy to use.
I have Martin Evening's LR book (ISBN 978-0321680709) which I really need to study some more - it's well written and illustrated but I haven't systematically worked through it, mainly because once you get the hang of LR it's so easy and efficient. I can see now that that effort may be worthwhile.
Michael Reichmann also has 9 hours of LR3 video tutorials
http://www.luminous-landscape.com/videos/lr3.shtml if you prefer that learning style. He also has a lot of other LR info and tips in free articles on his site.
Bottom line for me: I've ditched Bridge, and now use LR as my preferred tool for almost all my image processing, save for things that need layers or cloning. It's saved me a lot of time (better UI, faster workflow, simple to copy development settings to multiple images shot in the same lighting conditions), and also a lot of disk space, because LR's non-destructive edits are saved in a small sidecar file. It's easy to export different versions of the one image as new files if you need to.
Cheers,