This question is like asking what is the best type woman to marry.
Every one is different. The decision depends on what you like and what you want to do.
No kayak is best for everything. Some kayaks are not great at anything, but do well across several types of uses. You need to decide how you think you will use it and pick from there.
If you are going to use it occassionally in the surf at the beach, might like to fish from it, are interested in swimming from it on a lake, then consider a sit on top.
If you want a stable boat because you or your wife are afraid of going over, get a wide boat.
If you are going to do a lot of paddling in the open ocean or when there are windy conditions on the bay, get a narrow boat and learn how to control it.
If you are going to explore the marshes, get a short boat.
If you are going to paddle big distances, get a long boat.
And it never hurts to get a boat you think looks good and makes you proud to be seen with.
Click here for a discussion of kayak boat types.
My personal decision was a moderately long boat because I wanted to do distance, with some rocker because I wanted manueverability in the marsh, and a lot of bow volume because I didn't want to perl in the surf. So it is not as fast as some, it pounds some in head seas, and it is not as directional as some. But it does everything I need.
And its the best looking boat on the Bay - just my opinion of course.