It would depend on how they where converted. They are the raw date that goes
to make up the image, as such you can controll the convertion into the
finished image.
http://www.rawtherapee.com/

The results you can get after editing RAW are way way better than jpg, but it takes time and effort.

You will need a good package that can handle RAW - Adobe Elements 5 or 6 is a good start if you can't afford (or justify) the full Photoshop. You can download Picasa2 from picasa.google.com which will allow you rudimentary editing but not much - oh, and its free.

Get yourself a good book on how to edit RAW files, or get a photo mag as most months one or other of them has articles on how to edit RAW and usually a CDRom to go with it. Surprisingly Expensive World is a good place to look for photo books - then buy it from Amazon or wherever you can find it cheapest.

Finally be prepared to spend (cumulatively) perhaps 10 hours or even more to learn how to do it and get the right results. One tip: get your monitor set up properly - be that by hand or with one of the 'spider' devices that you can buy (at a price!) It's not a good idea to spend hours trying to get the picture right on screen only for it to print 20 shades light (as is usually the case!!)

Does not the 400d allow you to save as RAW and JPEG in one shot.  Should do
as the 350d does.  You can then compare.  You will also have a RAW version
for superior conversion (to TIFF etc) and image manipulation.

Shooting nothing JPEG is a waste.

MC

RAW files are differently formatted depending on which manufacturer
and even which camera I have just got a new D40 and was thinking of
playing about with some RAW files, however I discovered last night
that  my Adobe elements does not support the D40 NEF files although it
will support my Coolpix 8800 .  Elements / Paintshop pro etc, might
be  good enough with  with JPG files for now?

Simon

Its always far better to shoot in RAW for scenery/model photos - anything
that you want a high quality photograph of. (Different if youre shooting a
kids birthday party - jpeg is the answer there).
The biggest advantage of RAW Vs. Jpg is that the *adjustments* to the image
are far more subtle than you'll ever get from Jpeg - jpeg by its very nature
was created to that it *could* be compressed - this was the reason it was
created. If you get yourself the correct software for reading and adjusting
RAW (I use photoshop CS3) then you'll instantly see the benefits of it.

Rgds,
Kev