Very happy with my Westland "exact fit" cover for 8 years now. http://www.westlandcovers.com/index.php?page=products
Sunbrella for sure and buy a vented pole mount to make sure the rear and possibly the bow are tight and tented. Have a canvas shop punch a hole and ideally sew a reinforcement piece underneath
The full cover is great for stationary storage. I would never trailer with it.
If covered trailering is in your plans, a shop will likely have to custom make a cover due to snap placement.
I waited several years and a couple rainy pulls that lead to interior cleanings before pulling the trigger on a mooring cover too. It is truely awsome while trailering or for an overnight on the water to keep dew, bugs and wandering eyes out.