Really good advice so far! I just wanted to add that we hang all of our bikes upside down from the ceiling of our workshop. Eliminates the chance of your good bike getting knocked over, and save a lot of space. With 9 bikes in the family, this is important!

Use two per bike -- one per wheel! You can get the hooks at the hardware store. They look something like this: http://doitbest.com/Utility+hooks-Na...sku-233820.dib

(They cost just a few $ each in the local store. The price on this page is for 40 hooks.)