I believe the K100D and K100D Super have been discontinued. Newer models are the K10D and K20D.

Pentax is still using the venerable K-mount it introduced in 1975 so any older K-mount manual focus lens can be used with the newest DSLR cameras. There will be limited functionality (manual focus, stop-down metering) but they will enjoy the benefits of image stabilization since Pentax placed it in the camera body. If you have several K-mount lenses in good condition then buy the Pentax DSLR.

Since Sony bought the DSLR line from Konica-Minolta in 2006, the Sony Alpha (A) series cameras use the Minolta A-mount introduced with the Minolta Maxxum AF 35mm film camera of 1985. So any Maxxum AF lens will be right at home on the Sony A200 or A350 or A700. Sony also incorporates image stabilization in the camera body.