Where to stay?
The area with trendy restaurants and clubs is Calle Uruguay (map). Here are also many of the big brand hotels located, in big hotel towers. The area is safe and you can walk around to those places.
The old town is called Casco Viejo. This is a beautiful area, with old buildings (many are very old and awaiting restoration badly). It has many fancy restaurants and bars, and a few hotels.
The gay places are located in several parts of the city. Regular yellow taxis are cheap, it is just sometimes hard to explain where to go, as locations don't have street numbers.
Hotels
City