I encourage gamers/goobers to go and check out rpggeek aka Geekdo.com as they've really come a long way in the last couple of months. There's a lot of stuff there and the ability to search through by various things-- families, genres, systems, mechanics, etc. As more people rate their collections and review things it will become even more useful.
Starting Thoughts on Something I'm Going to Talk About Tomorrow
For mechanical aspects, it seems like most systems use some kind of combination of the following items: Characteristics or stats- usually representing inherent general ability in an aspect (this can be as broad as L5R's use of the elements for several different things; the classic ST, DX, INT; or really narrow sets like Manual Dexterity). Some may be figured from other stats. Skills- which generally represent training or knowledge of how to do something. Some may be “everyman” in that they represent inherent or instinctual ability. Skill lists may be less (Melee) or more (Fencing Saber Parry) granular. They can be a close list or an open creation exercise, and some skills may have specializations or the like. Equipment- the stuff you have and what you can do with it. Some equipment's independent of your character and some requires spending some kind or points or picks on them. Powers- things you can do. They're not necessarily a function of training, but can be. These include feats, magic, advantages, merits, charms, superpowers, and so on. Probably the biggest catch-all area-- usually defined as anything that isn't something else.
Different games will have different combinations of these things-- often equipments more an afterthought or an in-play item. Lighter games often throw away Characteristics in favor of skills. But usually you have, I'd say at least two of these different classes of things defining one's character. And usually they have a different mechanical basis or system. For example, in d20 your characteristics have a number and that number determines a bonus. That bonus then applies to other areas, notably skills. Skills have a number, but it is a straight value to which the bonus from the associated characters is added. Feats, then operate by a completely different but connected logic. The same thing with equipment there. GURPS, at core, has the same thing going on-- with feats being replaced by advantages. Some have closer systems-- such as Storyteller, but the applications and costs differ still between the two sides of skills and characteristics, and then the powers stuff builds atop that. Even something like Mouse Guard with its simple and stripped down system has a number of different mechanics, with not all of them acting in the same way.
On the other hand, in HeroQuest 2e, we really only have one thing: Abilities. You're entirely defined by your abilities, they cover everything listed above: characteristics, skills, equipment, and powers.
And they're all equivalent.
I'm going to talk about this in detail tomorrow and my thoughts on converting a couple of different games to this system. Right now my brain just hurts.