Chris, you didn't say how old your kids are, but if they are young I wouldn't recommend Los Cabos. There are some very nice resorts, but the beaches drop off quickly and have a strong undertow. There is really only one beach that is good for swimming. Don't get me wrong, I absolutely loved Los Cabos...just not as a family vacation.

I just got back from Aruba, and I would highly recommend it to anyone. Flights are good during the week. You can make it as cheap or as expensive as your budget allows. The beach is incredible, lots to do, tradewinds keep you cool. I stayed at the Radisson Beach Resort. $115 per night right on the beach. Very lush resort. A cheaper option would be either the Mill Resort ($65/nt) or the Amsterdam Manor ($89/nt). Both of these are across the street from the beach, but appear to be very nice. The Amsterdam Manor is closer to town. A taxi from the airport will cost about $17 each way.

Nassau is nice, but expensive and hard to get on a flight. Cancun has some good deals. If you really want to go cheap, take a taxi to the ferry dock and catch the ferry to Isla Mujeres. This small island has some beautiful beaches, pleasant hotels, and great restaurants (and cheap!), but very little night life. For about $50/nt you can get a bungalow at the Cabanas Maria del Mar right on the beach. There is not a whole lot to do there, however, other than lay on the beach.

Hope this helps!