OK, here's the deal. I currently own a Palm Treo 650, but I'm in the market to buy a newer model. Now due to my limited budget, I can afford either the Palm Treo 680 or the Palm Centro. However, I'm having trouble sorting out what's different between the two, besides the size (Centro is smaller). So basically... does anyone know which one is better overall? Why should I get one over the other? Etc etc etc. Thanks ahead of time!