You can always do batch conversions, but the main point of shooting in raw mode is that you can do very fine color corrections, gamma corrections, and other tweaks to get the best possible results. The process is analogous to carefully hand-printing pictures from negatives. If you shoot an entire batch with the same lighting, then you can apply the same settings everywhere, but otherwise you need to hand-tweak everything.

For the D-SLRs, there's a bunch of third party software (e.g., Bibble) that is widely considered to be better than the factory software. For the "prosumer" digital cameras, you're pretty much stuck. For Canon, there is a freeware converter tool, but it doesn't have any color correction features. It just dumps out TIFF or whatever files and you're expected to clean them up yourself, after the fact.