Like everywhere else you need to be sensible. I spent 3 years in LOS and never had a problem. Get a good local driver and use his local knowledge, I am guessing you areheading for Lagos, if so try to get accomodation on Victoria Island (VI) if not stay local to the Airport in Ikeja (GRA). Lagos can be a great experience, people are friendly however as in every country there are bandits who will rob you blind. Ignore most comments on here ref Lagos, as they are made by people who have either never ventured outside of the Sheraton or have neve been to Nigeria at all
PM me if you want more info