Lightroom 4 is out today, and the price has been dropped from previous editions -- $149 for the full version or $79 for the upgrade from Lightroom 3. Looks like a lot of retailers are out of stock at the moment if you want the box and disc, although that's to be expected on launch day, and those wanting to try or buy via download can get it directly from the Adobe website.
At that price, I might finally snag a copy. For quite a while I've been using PSE10 in tandem with Canon's DPP software that came with my camera, but it feels a bit kludgy in many ways.