Safety in Beirut
After 2009, Lebanon became a safer place and the number of tourists is dramatically increasing (more than 2 million in 2009), although the number has peaked since then. The US government's warning to travelers visiting Lebanon was lifted in mid-September 2009 but was later renewed, in part because of the risk of spillover from the Syrian civil war. The violence in Naher al-Bared has ceased. If you choose to visit Lebanon, visit the touristic cities like Jounieh, Byblos, Tyr and Tripoli. Beirut itself is relatively safe.
Photography of military personnel and installations is prohibited. You should also be careful in taking photographs in the Dahiyeh (the southern suburbs), if you don't want to get in contact with Hezbollah. The safest thing is to ask an official nearby for permission, although your request will very likely be turned down. Keep your camera in a purse just for safety. If a Hezbollah official approaches you, seeing your camera, he can't know if you've been taking pictures before that. Should you be taken in for questioning (because of taking pictures), remain calm. It might take a long time getting out of it, but it's highly unlikely that things should escalate or turn ugly. Bottom line: consider not bringing your camera at all. A trip to Dahiyeh is way too interesting and different to be spent getting questioned by the authorities.
Beirut sees no more criminal activity than any other major city, if not less. Be aware of pickpockets and scams involving overpricing. The last is mostly a problem concerning taxi drivers, so be sure always to agree on a price before setting off.