Looking to do some shopping on black friday, and wanted to get a mobile gaming device for traveling or between classes. I saw that the PSP is going for 130 with a game and a movie, the DSi is going for 140 with mario party, and the DS lite is just by itself but only 90. DSi can play DS games and is more upgraded but if I am not looking to play too many games on it what do you think is the better buy?