I haven't bought LR yet, I'm still playing with the free trial. While comments above are true to an extent, IME most of what is done in LR can be done in PS. Is it easier in LR? You bet! But most can be done in PS.
Global WB etc. works in Bridge, but it's not as elegant as in LR. I'm not a particularly high-volume shooter so LR isn't attractive to me for that. I'm starting to explore HDR shots and what makes LR attractive to me is the histogram. Makes picking shots to include much easier than the "trial and error" method in PS.
The only thing that remains to be seen is whether having a histogram for RAW thumbnails is worth $300 to me or not.
