What are some of your favorite RPG systems?

I personally recommend getting Champions Complete, which is HERO System 6th edition, the stats for the titular team, and a few other things all in one neat little package of about 250 pages. The alternative for Sixth Edition is grabbing two different books which cover basically the same material, only over a lot more pages. And of course, there's Fifth Edition, but I haven't done more than skim that one, so I can't really recommend getting one over the other.

Champions Universe is the setting book. Word of warning, they used the same name for the setting book for 5th and 6th editions. So make sure you get the right one.

For characters, there's Conquered, Killers, and Crooks and Villains, Vandals, and Vermin as the fifth edition Villain books, and Villain Vol 1-3(Master Villain, Villain Teams, Solo Villains) for 6th.

Setting wise, like I mentioned, Universe is the primary one and for Sixth edition has basically the whole setting inside. For Fifth Edition, most of the setting is scattered across a number of different books, but as a result, each bit receives more focus and detail than they got in the Sixth.

 

Expect a much more complex combat system. Much of the skill in running HERO is knowing when to use the rich rules of the combat system and when to make shit up to help it go faster or work better.

That said, it looks more complicated at first glance than it is. There are a lot of rules of thumb and fundamental design patterns that make things a lot more intuitive once they're grasped. Five Active Points is worth about a d6 of normal damage, ten Active Points costs 1 END point to use, fifteen is worth about a d6 of killing damage (and thus 3d6 of normal is worth about 1d6 of killing), and so on.

My favorite thing about the combat in HERO, as I said above, is how seamlessly it integrates lethal and non-lethal combat. Basically, every attack (with a very few special exceptions) has both the potential to knock an opponent out and the potential to kill him; there are two separate hit-point attributes, STUN and BODY, and all attacks do some of each, with the target's defenses applying to both separately. This lets the superhero knock the supervillain around all day long with his super strength without fear of killing him, confident in a non-lethal takedown, and yet still allows the possibility that this same superhero could hospitalize or even kill an ordinary crook if he isn't careful with his strength - all as a natural consequence of how damage is handled.

The messy treatment non-lethal combat in most systems is a pet peeve of mine, so a design that does away with the need for special rules for if the players decide to take prisoners is perhaps a bigger selling point for me than it ought to be.