I've got the Nelson Rigg cover. It wasn't too pricy and it doesn't scratch my bike. But if you want a real sweet one, and can fork a little extra dough, check this out: http://www.cycleshell.com/
That is f*cking cool!
Ducati badged ones are "water resistant" not waterproof.
All my covers have had the heat gaurd panel and I hate it cause through time you get all these little silver specks on your bike when you cover it. It doesn't hurt the paint or anything, it is just an annoyance that when you uncover your bike it is covered from head to too with it and I have to wipe it off.
I want a waterproof cover that does not have the heat guard.
My brother just got the www.cycleshell.com for his BMW 1150GS. He's garage-less, so he needed something that would work as a garage. That thing is solid. Really good materials and well made. Locks, too.
Have always stored the bikes in the lounge room - the other half is understanding! However when i have had to have them outside they are always covered with a full water proof cover. The simple rules are that
1) Never leave the cover on for more than 3 days without letting th bike breathe for a while (will sweat).
2) Be very carefull with any attachments suck as zips or rings pulls not scatching the bike when putting on or off.