The one thing I couldn't figure out this weekend if it was possible to do person to person trades like you can in Guild Wars 1. Is that possible or will it only be limited to the Auction house or Guild Storage?
The only way to do person to person trading is to use the mailing system. This is a deliberate decision to encourage the use of the cross-server Trading Post (auction house), to discourage people standing around in common areas shouting "Want to Buy/Sell/Trade", and also to discourage the likelihood of players getting scammed through those player trades.
Face-to-face player trading is not in game and will not be in the game at launch. In a fansite interview with Colin Johanson, the Lead Content Designer, he stated the following, emphasis mine:
As of release, there is no COD for mailing, which means it is still possible to be scammed through mail trading.