[Coda]

Well, I don't know if you can necessarily trust me at my word since I WORK for them, but yes, AdSense text/image ads are safe*. AdSense video ads are safe* but if one of your concerns is loading a bunch of videos that you're not going to watch, then it doesn't particularly matter how safe they are.

* Where by "safe" I mean that they won't do anything evil to your computer/browser/account/etc., although they're still going to track some information about your web-surfing habits. If this bothers you more than getting inane ads for things that you'd never possibly be interested in, you can turn it off in your Google account settings.