I'm a casual fan of the mash-ups; I don't care enough to go seeking out the latest, but I enjoy a clever bootleg mash-up when I come across it.
If you're like me then, you'll want to DL the Best of Bootie 2006, a compilation of 21 mash-ups from the past year (+10 bonus mash-ups). As with all mash-ups your mileage may vary, but for my taste they're an interesting batch. My favorite is the Chemical Brothers vs. Velvet Underground vs. U2 vs. Sugababes vs. MARRS track "Don't Hold Back, Sweet Jane."
(via Digital Music Weblog)