Bruce-
You'll definitely get better image quality from a used D30, if you can find one. It's got a bigger sensor and bigger pixels which equals better image quality. Some people felt that the images from that camera were too soft. But portrait photographers loved it - maybe for that same reason. You'll also be able to change lenses and use professional flash equipment with the D30. It does have noticeable shutter-lag, though. It's not as bad as most compact cameras, but it's definitely an issuse to be aware of.

As far as a new compact camera, Canon, Olympus, Fuji, Sony, Minolta, and Nikon all make good high-end compacts. Since you're already comfortable with the Olympus, I might recommend the C-5060. It will feel and operate very similarly, and it's a very nice camera, with a real wide-angle lens. The G3 is a very, very popular camera and a refurbished one would be a very good buy. It does still have noticeable shutter-lag, although it's faster than the G2. And as far as image quality, it's one of the best compacts.