Magic Mountain with fastpass - anywhere from 10-30 min
Animal Kingdom with fastpass - 20-40 min
Epcot with fastpass - 30-50 min
MGM Studios with fastpass - 20-40 min
Universal Studios - 10-40 min
Wet 'n' Wild - 30-50 min for the bigger rides
IOA - 20-30 min for DD, 1-2 hours for Hulk
Blizzard Beach - 20-40 min
All these times are from personal experience. I imagine that going around Easter would be better than Spring Break. I would also consider a day at Seaworld or Busch Gardens. Both have great coasters (Seaword - Kraken and Journey to Atlantis, Busch - Kumba, Montu, Sheikra)