Hamilton car cover is worth a shout, i have tried the cheaper alternatives which did my paint work no good and didn't breath well at all so trapped moisture etc.
A nice snug fit, not to tight but not like a flag in the wind either, breathable so does not trap moisture in, not made from cheap plastic crap either and is easy to fit by yourself.
Very pleased with mine and well worth the money i think.
Think I've got the storm force one and seems to be very good. Perfect fit and is properly water proof.
I had a small puddle of water build up on it, so is very waterproof. I have noticed I do get a small amount of condensation build up although it is breathable. Otherwise I am very happy with it