Hotel Porta Felice
Nice, spacious rooms with high ceilings. Great air con - you won't sweat in your room here. Staff are very friendly & speak great English.
The rooftop terrace (their restaurant/bar) has a nice view but is quite warm, very small & not as nice as the rest of the hotel.
Location is a bit out of the way, but it's close to the puppet, modern art museums and seafront.
It's in a quiet area during the day but livens up in the evening. Vucciria market nearby does amazing BBQ seafood (be patient it's quite chaotic) and there are great, cheap outdoor bars (tapas are free buffet-style with your drinks) and restaurants on and off via cassari, argenteria & bottai. You can buy cold beers & cocktails to drink in the squares and borrow bottle openers from the shops.