I started placing Google's AdSense ads on my individual archives about a month ago just to get a feel for the amount of money that might be generated. I'm happy to report that I've actually made quite a bit off the ads (people actually click on these things, who knew?) and see no real reason to pull them. Not only will this pay for the hosting, but it will leave me with a nice little chunk of change each month.
I've debated moving the ads from the bottom of each entry to being inline with the menu on the left, but I hesitate because I feel that that would look a little too "commercial," though it would surely compel more click-throughs. I'm going to leave them at the bottom of the pages for now, but might move them in the future.