Hi, I'm a fanatic about game design. Right now I'm really excited by 4th edition D&D. I used to play D&D when I was a kid, but when more sophisticated game systems came out I lost interest. 3rd edition was a very interesting improvement, but still didn't really improve D&D enough for my tastes. 4th edition, however, is totally different. It seems like a huge leap in game design, really a different game. This is the first game I've ever seen that looks like something I would design - a "game balanced" game. In 3rd edition, the different classes were so totally different, I couldn't even analyze whether they were balanced at all, I could only guess. The wizard had a whole bunch of annoying limitations about casting spells, but when he cast one, the effect was insanely superior to anything a non-spellcaster could ever do. The cleric was the ultimate healing god that you couldn't function without. I always felt these classes at high level were much better than the fighter types, and the fighters were there to distract the enemies and deal with ambushes. Who can tell, though, the abilities were so orthogonal.
In 4th edition, everything is built around a balanced design. Characters work in an identifiably similar manner, and the differences in things like hit points and armor class are far less drastic. The wonderful thing is that the characters still feel very different - something I've found challenging to achieve when trying to balance the game.