Just thought I would let you know about an offer on at the moment, IKMultimedia are currently selling their product DrummerTracks for half price!
"Use promo code: "DRUMS" on the IK Webstore and get DrummerTracks for half the price. That's $15 / EUR 10 each. Use the promo code as many times as you want, but you must hurry, offer is only good until February 28, 2011."
"It’s like playing along to the drum tracks extracted from your favorite albums. A wide variety of styles ranging from Classic Rock to ProgRock to Blues, Jazz, Funk, Soul, Country and more are available. It’s total inspiration wherever you go. Fills and variations for verses, choruses and/or challenging jam sections happen automatically just like they would with a live drummer."
Now, there aren't any great Metal Drum tracks that I'm aware of but there are some pretty good Rock tracks that may come in handy when you feel like having a jam by yourself!