Opera

Nicknames is a powerful feature where you can assign any combination of letters and numbers to a bookmark or a bookmark folder in the "Add current to Bookmark" dialog (Cmd+T). When you want to access the bookmark, you only type the nickname in the address bar or the "Go to Document" (Cmd+L) dialog. Opera then expands the nickname to the full address and opens that page. When combined with Keychain (Cmd+K), you have a powerful way to open pages and log in.