Very organic in her growth, the kind of player that uses multiclassing rules in service to the narrative as opposed to metagaming and min/maxing. Off the top of my head? Sumia, Melissa'a rogue/ranger/wizard from our Age of Worms playtest campaign. I've played games that I'm sure the developer felt was intelligent, several White Wolf games come to mind, but they aren't very good. The only non-RPG that I wish we could play more is Warhammer 40k. Not applicable, as my favorite RPG is Dungeons & Delvers and we play it whenever we feel like it. Initially I was going to say the 'easy to master' black box edition of Dungeons & Dragons, but then I remembered that we played a bit of OD&D once, and it was about as terrible as we expected.
