if you shoot and then check and have the possibility to shoot the same thing with different settings, then RAW often is not neccessary (thinking of the knifes here).
If however you shoot something, and you might never ever get the chance to take that special shot again (could be the special smile of your model you just captured once only).. then you will love RAW as you can improve the image much more than as if you had only the JPEG. Especially RAW contains more information in the shadows od your image, so brightening them up is much easier than with jpeg.
As for software, there is no absolute BEST .. it is again a question of what you feel most comfortable with.
I personally use Bibble, which is available for Linux, Mac and Microsuck ..
.. others might prefer Phase one, Adobe Lightroom, Apple Aperture, DxO, Breeze Browser (a fairly good one for canon), or whatever camera makers offer.
Some of them have trial versions on the web.. try them and decide yourself.