I have been to Barca a few times now and every time I have taken my camera.
I never carry my wallet when I am there, alwaysx just take money in my front pocket, However I did get my pocket checked when I was going for the tube when there this year.
I have heard some horror stories about Barca in teh last few months. There is a lot of forigners there that are not spanish and they are causing all the trouble etc.
When was I there last year I seen a guy getting beaten up for his point and shoot camera. Lucky his friend jumped in and they pinned the guy to the deck while sumone called for the Gaurdia.
I am going back in December, and hope to take my camera, but I always always keep it in my slingshot bag, tuck the zips in etc and it makes it harder to open without you noticing. When you have it out wrap the strap around your wrist a few times that way u can use it as a weapon as well
As for places to go, Visit the olympic stadium on the hill, and the palace, also the Nou Camp, the olympic village, La Ramblas, and the Fish market, the Gaudi park is fantastic. The Sagrida Famila is off limits to cameras inside but you get some great shots outside.
Port Viel is also nice, great views of the coast line and also the massive cruise ships. The cable car is a good trip as well as it offers a different view to Barca.
Mike