What do you look for in a role-playing game.

Talking purely mechanical here, I'm a student who very much wants to be involved in the design and creation of games in the future, what type of games I don't know but it's what I want to do no matter what.

So, out of interest and to create discussion: What is it, on a mechanical level that you look for, simplicity? options? openness?

Me, I love a system that has easy to understand rules, right down to it's basic mechanics, I don't like a system that is stuck in a single setting or would be hard to convert (I often read the books of other systems for material for my games, and just convert it).

For magic, I'm a power points kinda guy, having a reservoir of points to power your spells to allow flexibility is always something I enjoy. I also look for these sort of system to be reusable i.e A single pool of points that could be spent on spells, super powers etc.

Most my experience however is with D&D (mostly 3 and 3.5 so Vancian magic with different systems of other powers), but for the past year or so I've played more CoC and Chaosiums Basic Roleplaying. There was also a one-off ShadowRun game I played in but I found the dice rolling in that game tedious sometimes.

Anyway that is just a few thoughts that come to mind.

EDIT: Thanks for some great feedback guys, I'll be sure to ask you guys some things another time :)