I've been reading and commenting on a lot of blogs lately, and if there's one tip I could give just about everyone, it's Collapse.Your. Archive. You would have so much more sidebar room for blogrolls, book covers, and other interesting information, if your archive didn't drop down into a series of staggered clickable links that none of your readers ever use. See how nice and neat mine is at right. I don't usually place it that high either - it can live down lower on the sidebar below more important topics.
Collapse this. It's more information and clutter than anyone needs to see on your blog. Look how much room it hogs.
If you are using Blogger, click Design top right. Scroll down to the gadget that says Blog Archive and click on Edit. From there, you should see your other options. Then be sure to Save, and you should be all set.