Ed,

Without getting into all of the details at the moment, RAW files contain a lot more data than jpgs (and more importantly, that data hasn't be confined to a certain color temperature, contrast, color saturation, etc) so they will always give you better results than jpgs or 8bit tiffs, especially when you make the changes in Adobe Camera Raw instead of inside Photoshop. There is a HUGE benefit to shooting RAW, and the files are not outlandishly large... for a 10megapixel camera, a jpg should be around 3 megs (highest quality) and a RAW around 7-8 megs... and considering the cost of SD cards or Compact Flash cards these days, it's hardly worth worrying about. I've shot entire weddings on only two 8G cards.

However, the way that I demonstrated things in the tutorials applies equally to any type of image. You'll get better results with RAW or other 16-bit space images, but you can also get great results with jpgs [In the most recent versions of photoshop, you can actually open jpgs in Camera Raw, but they still don't have the same flexibility as actual RAW files.]

- Matt