I thought I've replied to this one, but here I go again:
ViewNX (basic, but a good reference)
Raw Therapee (quite a good one, but it takes some effort to get the colour warm or nicely saturated sometimes)
RawShooter Essentials - I still use it sometimes, good speed of previews, although the conversion quality isn't the greatest, but still decent most of the time
UFRaw (I like its colours a lot)
LightZone isn't too bad either, at least the last downloadable Linux version of it.
Capture One 4 wasn't bad either, although you need quite a bit of tuning to avoid muddy photos at higher ISOs, but I think it's still better than Lightroom (where you pretty much shouldn't sharpen it at all)
Lightroom - that one I didn't like
Bibble - not much of an improvement over, say, Raw Therapee.
dcraw with a few batch scripts - it's what I use most now in Windows. Excellent highlight recovery abilities and good colours too. If someone would like me to send them those batch scripts, send me a PM
