Flash RPGs are pretty fun. When you're not playing RuneScape, try these.

King's Island: Play as a warrior who tries to re-establish the king's law on his land full of rebels.

Mardek: Chapter 1: A story-driven RPG. Mardek and his friend Deugan are heroes on their way to slay a dragon and save a princess.
Mardek: Chapter 2: Chapter two of Mardek, featuring around 10 hours of gameplay.

Sonny: Play as a zombie and fight for your life in a crazy and twisted world.
Sonny 2: Version two of Sonny, with hundreds of new items and a voiced storyline.

If you know any others, post them here.