There is absolutely nothing you can do to an individual file that you can do in Lightroom that you cannot do in Photoshop. Nothing.
There's plenty you can do to an individual file in Photoshop that you could never do in Lightroom.
Lightroom is all about high volume work.
If you need further clarification, please ask in the Lightroom forum:
I've tried to get into Lightroom. Really tried, paying for version 3 when it still cost real money. I have books on my bookshelf, and a few Gb of video tutorials, but I just can't make myself interested in it. I do a fair bit of volume work, often with one or more second shooters who pass their RAW files to me, and I can whip through them PDQ using Bridge and Photoshop with an Action or two. I have a reasonable DAM policy that uses Bridge and the excellent search facilities of Windows 7, and can always find a picture from years ago.
Out of bordem waiting for the CC to live, I have installed LR5, but havn't opened it yet, and I have a feeling that I never will. A lot of my photographer buddies love LR, and some of those are really good with Photoshop, but I don't feel in anyway disadvantaged doing high volume work with Bridge and PS.