Geeze, I play a lot of RPGs but I mostly stick with popular titles and 'secially Square's. Even Super Mario RPG, as awesome as it was, is starting to become a sleeper hit so it's really hard to say. This thread does bring a few new things into my radar but not a whole ton to be honest.
Since we're not being purists about it though, I love the Escape Velocity series.
Escape Velocity Nova is the only shareware game I've registered to date and is advertised to have RPG elements. I'll admit there are some like the shops but there really aren't too many conventional RPG mechanics and plays a bit more like a super advanced version of Asteroids, kinda. On the other hand, it captures the heart of what an RPG really should be; that is, allowing you to play virtually any role you like in its immersive sci-fi setting. You can choose to be a part of one of any of the six main storylines and twelve subplots, as well as having a plethora of side options available to you like space trading, piracy and courier service. Getting even further into the being anything you want to be aspect, the game has an expandability aspect, which allows for add on content like plug-ins and total conversions, if you find yourself bored with the regular game. I've spent many an hour, attempting total galactic conquest.