I find that a bit far-fetched. If you can prove it, though, that would be MAJOR news and I'd urge you to follow-up.
You weren't, by chance, also searching for items related to what was on your desktop?
Say, you are obsessed with Paris Hilton. Your desktop is filled with Paris Hilton video and audio clips. (Whah! Whah!) I'd bet you've been doing a few searchs on "Paris Hilton". I'd not be surprised if Adsense comes up with Paris Hilton-related ads. (As well as "Hotels in Paris...")
Google doesn't say much about their algorithms, but I've never much emphasis on the notion that they use search history to determine ads that are displayed. This might be an indication of a change in direction.
[edited by: jtara at 9:37 pm (utc) on June 10, 2007]