The following have proven themselves very useful to me in digital photography. You may want to look into them and see what you can use.

GIMP - open source, free equivelant of Photoshop. Very handy for minor clean up, layering, and pretty much anything that photoshop can do.

RawShooter Premium - allows you to tweek exposure, colour balance, highlight & shadow contrast, colour tempreture and many more settings in the RAW format, without actualy changing your RAW file. Will save to TIFF or JPEG format. Also supports cropping, sizing, histograms, tint, sharpness, and noise suppression. If you only buy one program to use with your camera I can't say enough about this one.

ACDSee - I'm a little biased on this one, I've been using it for years and love it. Great for batch re-naming of files sorting and viewing, creating thumbnails and contact sheets. Also includes an editor which is substandard. (It has problems working with TIFF images) but is fine for Jpeg or BMP. I use it mostly for viewing and sorting pictures for the UF_DPC. Great features for the price.

EXIFER - Postcardware (if you like it, send the author a postcard). A more advanced program but handy to have allows you to read & write EXIF data to your pictures. Include copyright notice, details on the pictures and other imbedded information that you may want to keep with the picture. Most cameras include exposure settings, date/time information and camera type along with an assortment of other information such as if the flash was used, lens length appature etc).

Shameless plug: UF_DPC diary and the Gallery and tutorials