alexb,
I've got a 6m 'tinny' (Savage 'swordfish', with 115 Johnson). As mentioned above, FG will give a smoother ride, but if you're towing a fair distance, they weigh around twice AL. Plate hull AL boats have come a long way...I've modified mine with an AL checkerplate floor, and underfloor fishtank. Carpet keeps the smells in.
...also, I'd be looking at a 4cyl motor, more economical (by far) and quieter.
Geelong Boating has 'Razerline' boats (made in WA?) Goood looking AL plate hull boats, mixed reviews...worth a test drive though. Also, from my own experience, you cant beat either barcrusher or stabi hulls to fish from
...as for skiing ? - that's more about the motor noise, graphics & soundsystem!