I forgot to mention this earlier. Bibble 5 is out, and it's exciting. It is for asset management, just like LightRoom, but it has some different features to LR, making it a slightly different tool. It's available on Linux, Mac, and Windows. I'm drafting a review of software for use on Linux, so soon you'll see more info about this (I've already given the free 14 day trial a go). Site:
http://bibblelabs.com/ It's slightly cheaper than LightRoom, too; USD$199.
A quote from the draft I'm writing on p4:
It has to be said that Adobe now has serious competition lurking.
