That is a loaded question!!!!!!!! I personally use a 16ft Lowe, with a stand-up center console, and twin Merc 35s with jet pumps. I wanted something to get around in the small creeks off the Tanana river. Also it usually is just me and the wife, and this size boat is just right for us. For the Yukon I recommend something bigger, a lot bigger. What ever you get just make sure it has jets, props don't last long here.
I have been looking at the Predator Sport John, an inboard jet. It's a nice boat, and the wife is looking for a bit more comfort now that we are older. It's just a very expensive unit. There is lots of differant units out there, you just have to decide what you are going to do with it, and how much you are willing to spend.