The d20 system is the new system from the boys at WotC. That's Wizards of the Coast (that's right, the Magic: the Gathering boys) to you people that can't sling the lingo in roleplaying circuits. Using their new D&D 3rd edition as an excuse to develop their very own d20 system, they've also released (or have / are planning) d20 settings for Legend of the Five Rings, Star Wars, Dune, Wheel of Time, and a few others as well.

But wait, there's more! The d20 system is an open system, meaning that anyone can write stuff using their d20 system - as long as a few provisos etc. are met. These files are conveniently available as PDF files at the TSR website.

Personally, I think I like it. Though it lacks the charm of good ol' AD&D 2nd edition, the new d20 core mechanic is amazingly flexible. Most anything can be defined as feats, and are thus selectible. Same goes as for core classes and prestige classes. Very nice, and very chic.

But, I won't use the d20 mechanic for everything - though, if you want, it's possible to convert anything into the d20 mechanic. Me, I'll still play Shadowrun the good ol' way - with lots and lots of d6 dice. I like rolling a lot of dice. That, and I have a hell of a lot of material for Shadowrun. Same goes for good ol' WEG Star Wars as well. d6 is the way to go - especially if you have a lot of old material for the old systems like I do .