Another Aussie band is The Whitlams who have been popular for years now. Personally I find them a little dirge-like and mournful but everyone else I know that likes Ben Folds is a fan of theirs.
The classic player was Leon Russell – check out the Joe Cocker album Mad Dogs and Englishmen, for which he was the musical director (and did some very funky playing).
Madness had a number of songs with prominent piano parts (off the top of my head, “Disappear,” “Shut Up,” “The Sun and the Rain,” and their version of “Swan Lake”). And (from the same producers, coincidentally or not) Elvis Costello’s album Punch the Clock has some wonderful piano on it.
If you want to explore the avant-garde side of piano rock a little more then checkout anything by Emerson, Lake & Palmer. Specifically…their album Brain Salad Surgery.
Augustana recently had a hit with their song “Boston”, which I thought was quite good. From a quick listen to iTunes’ samples of the rest of the album, however, it seems it was the lone piano ballad on the album. Disappointing.
I second Ben Folds.
You ought to check out his myspace sight and listen to the song bitches. Haha… that from the guy that wrote the soundtrack for Over the Hedge.