If you visit the same collection of website every day, this will save you making multiple trips to the bookmarks menu.
Launch Safari and make sure tabbed browsing is enabled. (In the Tabs section of Safari preferences make sure Enable Tabbed browsing in clicked)
Click on the bookmarks button and create a new folder, giving it a descriptive name. Copy/Move all your favourite bookmarks into it, and drag it to the bookmarks bar.
Then enable the "Auto-Click" option next to the folder. Now a small square will appear next to your bookmark folder instead of a downward arrow, and when you click it, each site will open in a separate tab.