Do I need Lightroom if I'm a seasoned Photoshop user?

As you suggest Lightroom is for organization and batch editing - basically photo management. It does these tasks very well. It is not really useful for editing single photos beyond some very basic tasks... If you are skilled at Photoshop you will be disappointed in the editing capabilities of Lightroom.

I also like that there are plugins like VSCO that make shots look warmer, more like printed film. I know that's cheating. Wait, what? How is that "cheating?" I won't get into the philosophy of it, but this is *exactly* what Lightroom is for- color correcting and making photos look great. They call it "develop" because these are the same choices people used to make in the darkroom, or in their choice of film. Photographers have always made choices to get the look they want and it's not "cheating" in the least. If you think of "editing" as literally changing the photo- moving things around, making people look skinnier- than yeah, Lightroom doesn't do that. But if you think of "editing" as adjusting the color and look to make the picture beautiful- Lightroom is great at that.

I said cheating just because older-school photographer friends who are accustomed to developing with film think it's silly to shoot in digital and then make a bunch of edits to make it look more like film. I'm not particularly hung up on it. Probably better for separate conversation.

It is not really useful for editing single photos beyond some very basic tasks... I disagree. A professional photographer friend has a 100% Lightroom, 0% Photoshop workflow, and what he pulls off in it is amazing. I've seen his before/afters and it's striking. For my own photos, I'm a dilettante and I find it a lot easier to get a photo to "pop" in Lightroom compared to Photoshop.

Let me soften my comment somewhat - Lightroom can be very useful in adjusting the development of digital photos (color, exposure, white balance, crop, noise reduction, etc) - especially when similar adjustments are applied to a large number of photos. I use it in this capacity all the time. However the adjustments should be viewed as a subset of the adjustments which can be done with Photoshop. Some of the adjustments can be done much quicker with Lightroom for sure, but I don't believe Lightroom provides any "Photo Editing" capabilities with are not replicated in Photoshop. I think it's generally accepted that Photoshop provides significantly more capabilities than what you get with Lightroom. They are two different tools with two different primary functions. Both are exceptionally good at doing their primary function. Photoshop is for editing photos. Lightroom is for managing digital photo workflow from import to export.

I'm pretty good at Photoshop and a heavy hobby photographer/semi-pro and I use both. First I'll upload my batch of photos to Lightroom where I can quickly go through the one I want to keep and remove the ones I don't. Then, Lightroom is easy and quick to do all of the usual adjustments - cropping/exposure/color balance/vignetting. Then I'll take the best few photos of the bunch over to Photoshop where I'll do things like touch ups, burn/dodge and transparency masks to get the final look right. They work together like a well-made team.

Lightroom lets you share edits across many raw files much more easily. Have 10 photos shot in the same environment & settings? Color correct one of them and then apply the changes to the other 9. I find myself only using Photoshop to do complicated retouching.

Lightroom has a free 30 day trial, why not give it a shot and decide? I switched from Photoshop to Lightroom for my amateur-level photography a while back. Truthfully most of my photo editing was in the raw converter, and that's essentially the same code in both Lightroom and Photoshop. And Lightroom is just a lot simpler and streamlined for editing individual photos. But where Lightroom really shines is working with groups of photos. Adobe Bridge or whatever nonsense Photoshop had never worked for me. Lightroom is great at importing a bunch of photos, choosing the few good ones, tagging them, mapping them, developing them, uploading them to Flickr.. All that stuff is way way easier in Lightroom. iPhoto, Aperture, and Picasa all do similar things here at various levels of professionalism. I like Lightroom best. BTW with the new Adobe pricing model the cost equation on this stuff is changing. Lightroom is remaining a single boxed product, not a subscription fee.

I used to use Photoshop exclusively, but now I only use it when I need to make pixel-level changes (head swaps, cloning, etc.) And as it's been said already, it's great for keeping photos organized, and for uploading to Flickr, etc.