Remdrake,
There are several good posts on this topic. Try the search feature. I just recently purchased a Harbercraft 1600 with the intention of putting a pump on the back and running all the types of water you are talking about. When I was searching I realized I would have to compromise and settle on a boat....my boat is fairly stable in the salt, but won't run real skinny water in the rivers. So far I'm happy with my choice although I sometimes wonder if I should have gotten into an 18 foot model.

Buzzo,
Interesting question....my boat has the exact same dimensions as the 18 foot model except 2 feet shorter. I've been told by passerbys I wouldn't have any problems taking her out of Westport. At the same time some guys I've talked with who fish off the West side of Vancouver Island recommended NOT taking any boat less than 18 feet offshore. I personally think my boat is going to be as sea worthy as a larger boat (18ft) with similar specs. However, all this speculation is dependent on weather and sea conditions. If its anything other than calm with no wind I wouldn't be comfortable in a boat under 20 feet and preferably larger.