best boats for family?

My hubby and I have about 20K to spend on a boat - awe have three small boys 2,4,& 6 so we need a boat that does it all - any reccomendations? We want tot ube, ski ect...but relax as well...and I know - I've heard the whole "a boat is a hole in the water to dump your money", but we have the money, the economy presents us with the opportunity to get a great deal and my hubby was raised on the water - so he wants his boys to be too...so any suggestions? Pontoon? Deck boat? Bowrider? Thanks in advance for any advice...we have a family member that owns a marina and is offering to sell us a brand new 2008 Bentley Pontoon Cruise 24 foot with upgraded 150 hp motor with everything thrown in for 19k....take it or keep looking?