If you're not using Keywords, you're missing out. It's the fastest and most flexible way that I can imagine to navigate around frequently visited sites.
To set a keyword, bookmark the site, then press Shift+Ctrl+B to open your bookmark library. Click on the bookmark then at the bottom you'll see the attributes Name, Location, Tags, Keyword, and Description. Whatever you type in "Keyword" will become your "shortcut text" to that website. From then on, type that text in the address bar and hit enter and you go straight to that site.
For my most frequently visited sites I assign a one-character keyword. For example, my keyword for Gmail is simply "g". All I have to do is press "Ctrl + L" which takes me to the address bar, then press "g" and "enter". It's just as fast to open it in a new tab: "Ctrl + T (opens a new tab with your cursor already in the address bar)" "g" "enter"
Whenever I find myself visiting a site over and over, I'll create a keyword. Facebook is "f". I have a keyword "phillies" which takes me to the Phillies schedule on Yahoo Sports. When I was learning how to maintain my pool this summer (my first pool), I visited this site a lot, so I assigned it the keyword "pool".
I try to play "A Google A Day" everyday, and I assigned it the keyword "game".
With my hands on the keyboard I can literally open any of those websites in under half of a second (okay "phillies" might take a full second).
Give it a try...it's a huge time saver!