I would be inclined to say that if you purchase a dual engine boat you effectively put yourself out of enjoyable tubing/watersports. It get's pricey fuel wise.
The age old debate of 1 engine vs. 2 is one that is discussed frequently. If it is your first boating experience you might indeed want to get a nice stock powered boat for the summer, and get your sea legs during this first year of ownership. The real thing to think about with 2 engines is maintenance and insurance - not fuel costs. Twice as much everything. The rest of the decision really depends on your boating circumstances.
Check out all the owner's forums below because there are alot of neat boats available in that size/price range.