Petco is one of my favorites (been to around 8 games there) as I am in SD for work quite a bit. I love those old school Padres jerseys. Stadium is right in the Gaslamp so lots of bars and restaurants around. The hotel (Hilton Bayfront) I stay at is adjacent to the park and to the SD Bay.
FYI, there is a local train that brings you from downtown SD right to the stadium in Anaheim. Good way to go to the game without driving.