Before you take the plunge (excuse the pun) I would really try to get across to Ribex this weekend, if the Ribshack idea then takes your fancy they are also there with almost every other option from new to second hand. Also a good time to ge out in the RIBS on The Solent which I believe you have said is the area for you presently.
If you wnat to go further afield dont forget what is towable with your car etc, Again Ribshack have just expanded their area of ops to further afield which might open up some more for you, They also offer powerboat training with their deals. What ever you choose dont forget to get training. Good hunting