Take a look at KD River cruises - web site www.rivercruises.com
We like the looks of them, and they offer some great itineraries.
We are thinking seriously of a Rhine or Moselle trip in the late spring of 2003.
Many of the Uniworld 'ships' are getting a bit long in the tooth (and I'm pointing fingers?) while KD recently merged with another company so they have a lot of different itineraries, and they got the Conde Nast readers choice award in 2001.
Dall (and yes, it's MUCH colder up our way, but we'll be nice and toasty warm in 11 more days!)