take the oxford cover very high quality stuff, protects against all kind of weathers. i use it and it keeps the dust from coming in to the bike as well as rain and other stuff. if you live in a very rainy and windy area this is your best choice as it has buckles from the bottom so you can close it from under your bike so it wont fly away in a windy day.
+1 For the Stormex. Buddy has one for his CBR and doesn't have a garage or shed, just a little patio. I watched that thing take a beating in a thunderstorm and never shifted on the bike. If your bike will be outside temporarily, you can also check out Oxford's Rainex cover.