I started with D&D, played GURPS for years, HERO (champions and Fantasy Hero), have played Savage Worlds recently, a bunch of WFRP 2nd edition (a tiny bit of 1st edition), Call of Cthulhu small amounts, Shadowrun 2nd edition, Shadowrun 4th edition, Dark Heresy, and some others scattered through.

Character philosophy: all adventurers are at least a bit crazy if they choose to be adventurers.  I don't play evil characters and such, but they tend to have extreme personalities.  "Sir" was a superhero who was almost invulnerable and would not avoid being hit (once he stepped out of the way when an alien spaceship blew up the building he was in) he postured and gave speeches and was confident that no one could take him out.  Chosen Savior was a fantasy hero character.  A librarian, he decided at old age that he was chosen to save the world.  He brought his book and a mace and went out to do so.  He was insane and had a very strong will and was very persuasive.  He gave lots of speeches (being fantasy hero he could get bonus damage if he made an oratory skill roll when attacking).

I want my characters to be good at one or two things and not do other things.  I don't regard this as min/maxing, I regard it as having a role.  My current Shadowrun character is a generalist, which makes him feel like a sidekick - there is a never a time when he is needed, he just helps out.

As a GM I don't like adventurers.  I tend to create one shot modules more like books or movies.  For instance a Star Frontiers game, the players were forcibly hired to go investigate why a deep space monitoring post had suddenly gone silent.  Most of the character's died, but they won.

I don't like the random adventure of the week.  I like short, tight adventures, or long storylines based on the characters.  I had a GURPS game that I ran for about 4 years.  The characters were saving the world, but they were designed with goals that guided what they did.  They weren't just caught up in random events.