Damn RiK, you got that right, war of the worlds cover by alchemist is one of my all time favourite tracks, so powerful yet gloomy...
Some of my favourite covers:
-Monster Magnet doing "The Right stuff" by some old concept band (forgotten the name), its on Monolithic Baby! (not released here yet, got mine from europe). And their cover of Into the Void
-Metallica doing Last Caress, and Astronomy (love the big guitar bit fading at the end)
-Megadeth "The mechanix" which is arguably a cover of The Four Horsemen, arguably...
-Frankenbok covering Don't Call Me Baby by madison avenue (sp?), pisser!
-Megadeth doing Paranoid, awesome!
- Foo Fighters - Baker Street
and theres a lot more good ones, however my brain is good at remembering tunes but not names, not to mention how complicated it becomes remembering covers..