If you haven't yet downloaded the new beta for LR 3, I recommend giving it a shot.

There has been a lot of rework under the hood
and runs a bit smoother than before. A lot of new features such as adding grain, a completely redesigned import that supports more formats, presets, and browser like capability.

Thumbnail scrolling is significantly faster.

Develop has added in much better sharpening, color noise reduction, a simplified local corrections panel and many more.

Output is significantly improved.

I could go on listing improvements and sound more and more like a used car salesman who has read a manual halfway, but I won't.

Here is a link to the public beta. Give it a shot.

http://labs.adobe.com/technologies/lightroom3/