For a wee while I've been using EZDrummer from Toontrack for my drum tracks. Loads of drum samples wrapped up in an easy to use interface, with the option to create drum tracks using the tons of midi file drum patterns included or indeed just creating your own in your sequencer - or a combination of both of course. I used it on my entry to the EV covers competition (in the "originals" category).
I d/led a copy from a torrent site and tried it out - then found a good price for it online and bought a legitimate copy. Its superb. Have to say its really easy to get good natural sounding drum tracks from it - and as a registered user I got the chance to upgrade for half the normal price to the "big brother" version "Superior Drummer 2" which offers even greater flexibility, sounds and options.
Superior Drummer 2 is around £200 - I upgraded for £68 this week. It just arrived today...on 5 dvds - I may be gone some time...
Well recommended for drums - acoustic, rock or electronic, they cover them all. EZDrummer Superior Drummer 2