Charlie - I love the keypad entry. We don't have any kind of alarm yet, although I'm thinking we will eventually add something like this
http://www.ravelco.com/. This was recommended by Herb (Bronco Hauler) on this thread:
http://www.sportsmobileforum.com/viewtopic.php?t=381.
We surf almost every day, so it is incredibly convenient for us to get back in the van after surfing. Especially since we may get out of the water at different times. On my old truck, we used to lock the key on the rear hitch in one of those key locks that real estate agents use on the front doors of houses for sale. So far we have been leaving our keys in the van. I will be keeping a key hidden in/on the van as well in the off chance we happen to lose ours. We will not be doing this in areas where it could potentially be more of a problem (e.g. sketchy areas).
We mainly got this feature since we travel to a lot of remote spots. I figured it would pay for itself after locking ourselves out just once and having to break a window to get back in.
Just to let you know, my theory on break ins/thefts is that if someone is motivated enough they are going to break in. Obviously, you should make it difficult for them and you should also use some common sense.
Just my two cents worth...