CS4 and LR

I'm buying CS4 for a new system. I know Lightroom has a good cataloging system, but as for post proccessing is anything gained by also installing LR (in addition to CS4)?
Thanks

PSCS4 + Bridge do most that LR2 does.
There are a few minor differences, but not worth buying LR2 just for those processing differences IMO.

If you need CS4, then I'd say get it and take time to get up to speed with it. As you go, read up on what a program like Lightroom offers (integrated interface, including organizational tools and the same Raw processor "engine" that PS uses and easy-to-use integrated tools for development and output) and, at some point if you feel LR will offer substantial value get the LR free trial and decide for yourself.

If you shoot Raw and find yourself spending more time in ACR than PS proper, and if you are shooting at a volume that makes image organizing/managing a growing need, then Lightroom can work well as a "workflow manager" with Photoshop as a powerful image editor.

You can do everything LR can do with CS4 and bridge. As mentioned above if you shoot RAW then ACR is the same as LR except LR has the organization end covered. Easier to go threw your files also you can create different catalogs to separate different styles from each other, like motorsports from wildlife from landscape and so on. That way when you just want to see your studio and modeling shots you open up the catalog you created for your studio and modeling shots and so on. You do not need to have both it will not give you a better post result.

Sevan

Simple point here.......

LR is for doing large quantity of images where PS is for doing work on single or small amounts of images