Royal Caribbean still has the largest, with their "Voyager" class ships around 142,000 tons. These ships are wonderful for cruising with family/kids or groups. Lots of onboard activities, definitely worth cruising on!
Voyager of the Seas does western Carib year round from Miami,
Explorer " " " " alternating eastern and western from Miami
Adventure of the Seas (actually only 138,000 tons according to the RCCL web site)
does a southern route (Auba, Curacao, St Martin St Thomas ) from San Juan, year round