The Island is the way to go...if you're married...you're BAH ($1023) covers most or all of the cost of living in a standard duplex on the island.
If you're single, you BAH ($744) will do you quite well at the Beach Club. However the best deal for the single guys is getting a roommate or two in which case you can make some mad cash on a house or duplex on the island.
Money asside...i'm with the rest of these guys...the island rocks