Paul raises some interesting questions in his comment to the previous post which I will address.
Why TIFFs or RAW rather than JPEGs.?
The answer to that one is that JPEGs deteriorate everytime you save them. They were never intended for permanent storage but rather for viewing on a computer monitor or sending by e-mail. Its compression also renders less desirable prints. TIFF is a permanent file and does not deteriorate. It also is the format of choice for printing. Of course it is a much larger file and not suitable for posting on the Web or e-mailing.
RAW is a different critter altogether. It's big negative is file size. My 8.5 megapixel camera pukes out 25 meg files in RAW. They are just frickin huge and have necessitated buying an external hard drive for storage. With the advent of USB2 connection though, that is a minor problem and external hard dtives are pretty cheap. My 200 gig hard drive cost about $130.
RAW is just what it sounds like, it is all the raw data that the camera received when you took the picture. This allows you to make the choices in the convenience of your computer that you would normally make on the fly in the field. The big issues, for me, are white balance, tone, contrast etc. All that can be done easily from RAW at home where you are more or less locked in when shooting JPEG, not to mention the lost data in JPEG due to compression. There is no way a 2.5 (or smaller) megapixel image has the info a 25 meg image does.
When the RAW processing is done, I save the image as a TIFF which is a much smaller file. When satisfied, I can delete the RAW file... but have not done so as yet. It's like throwing out one of your children!
Now,as to Lightroom.
First, it is MUCH cheaper than PS CS. Just now you can get it for $200 as opposed to $600 for PS. Secondly, for workflow, it is WAY simpler and better organized than PS and is aimed at the photographer and his needs as opposed to the publisher, or occasional reporter screwing with war photographs trying to make the military look bad. I was a beta tester for Lightroom and just could not be more impressed.
Lightroom is a bit of a memory hog. I have 1 gig of RAM and it works fine. But, if you have a bunch of stuff auto-running on startup, 1 gig might not get the job done. When converting JPEGs to TIFFs I did start having memory problems after about an hour or so. But how often are you doing something like that? Normally I'm just working on fewer than 100 images after a shoot, and I have never had a problem.
Well, there are my answers for Paul.