Gearbox updated the Borderlands 2 website to include the skill trees of all four characters. The skill trees are interactive so you can see how the point assignment flows and map out in advance how you think you'd like to build your character. As in the game, each skill provides a detailed description if you hover over it. When you're finished, the Skill Tree calculator tells you what level you need to obtain with that character to create your build in full.
Recently, Randy Pitchford was on site at IGN and participated in an hourlong live stream with a couple of the IGN folks. He answered questions via Twitter, gave tips to the IGN guy playing and talked about the game in general. They demonstrated "Bad Ass" points and how they affect character development. You earn coins from completing side missions and challenges which can then be cashed in for "Bad Ass" points. When you cash coins, you get to pick one random stat out of a game generated list. This stat bump is profile level which means that it doesn't matter which of the four characters you play as, that stat bump applies on top of whatever individual character specific skill tree options you built out. Randy says that while character rank is capped, Bad Ass rank is not.
Another nugget of information shared was that you collect Iridium which is used to unlock endgame areas and content. End game content is usually where these types of games fail but Gearbox designed Borderlands 2 to be a hobby game. There will be plenty to do, find and explore long after the story line is finished.