well there's many factors to consider, are you going alone to get laid
or with the wife and kids or with the boyz, what kind of activity you wanna do, swim with dolphins, waterfall climiming, relax on the beach or just walkin the town.
A sea view in my opinion is the only view you should get.
Different ship have different lifestyle some more fun (get drunk, get laid) some more relax, other are just classic beautiful ship but a little boring.
Carnival Cruise Line is the cheapest in most case, and also the youngest crowned, so the bigger party and losts fun (thats why they are call the fun ships)
to choose the ships, take the newer ship because they have more to offer.
In royal caribbean they have a ice skating ring and a stripmall in their bad boy ship. (but the party fun level is lower) maybe cause there's to much to do???
I won't name the rest the companies my finger are getting tired
last for island my top 5: st lucia, st bart, naussau (bahamas), cozumel, bora bora.
don't forget Hawaii can't go wrong there.
Hope that helps