SD990 is pretty nice no? I know the SD880 was a great performer, but the SD990 (while it does bring more resolution), packs a larger sensor (1/1.7"?) as opposed to the 1/2.3 or was it 1/2.5 of the SD880. Basically the SD990 packs a G10 sensor, and some manual control. For a dumb shooter like my mom (no offense), she's seen night and day improvement compared to shooting on her old SD600.
If you want a prosumer grade, I'd get a Canon Powershot G3 or a Panasonic LX-3.
If money is no issue, I don't see why not DSLR, but I actually do recommend people to avoid DSLRs. It's not so much an elitist thing, but if you're doing casual pictures, you do it well with ANY P&S. Just learn to take pictures well. DSLRs aren't going to magically make your images better. Learn with prosumer cameras how to control exposure settings and lots of other things and to deal with RAW images. See if photography is the thing for you. Don't fall into the trap of "omg I need better equipment." Honestly, I hate seeing my friend and his XSi take some pictures and whine about how he needs full frame and "L" lenses. Some of his pictures look disgusting even after post processing. He hasn't even learned basic framing and composition. And to top it off, the images are beyond soft (probably terribly focused). I wanted to slap him in the face and take some shots on my G3 to prove him wrong, but whatever. Even casual shots with my T1i and kit lens yields better results (like not even trying to be artsy). If photography isn't your thing, better equipment won't even save you.
If you really can master that all and want more, then I see no reason why not to go to DSLRs. I'd skip the D3000/XS and jump straight to D5000/T1i/Pentax K20? But why not D90/50D? I personally went for the lightweight, but the Nikon D300 and D700 as well as the Mark 5D II are amazing. Sorry, the D3x and 1DsIII are just beyond me. They're amazing, but I can't see myself holding a machine gun walking around. I still like compactness. I'm not at the point where I need some insane equipment yet.