Steven Slate drums are awesome if you are doing straight up sound replacement on crappy sounding drumkits (like with Drumagog or similar) on rock/metal.
Addictive drums has really got some of the best sounding snares and toms for rock, metal or any other genre that has real music in it, that I've ever heard, but it's a stand-alone vsti, so to use it as a sound replacement tool, you have to first export your triggered drum tracks as midi data with drumagog or something (which makes sloppy "can't play to a click track" drummers a billion times easier to edit anyway) and then route that data into addictive drums.
Then have the drummer do some clean cymbal-only overdubs (because sampled cymbals are usually totally lame...) and you should be blown away at your final result.
Addictive drums kick drums are kinda lacking, though...they all sound too.....real, I guess. I know a lot of old-school "purist" type people would prefer to have kick drums sound like you're beating a cardboard box with a wiffle ball bat, but I prefer the thump/click sound that makes everybody (including whoever's paying for my time) go "WOW! That's PERFECT! - How'd you ever make my crappy kick drum sound like that?! (LOL!!)" Those samples are not really in
the Addictive drums instrument, however, I'll stress it again that the snares and toms are fantastic.
Anyway, as far as just straight up sample packs, though...Steven Slate are some of the best, along with Purrfect Drums. Anything recorded in BlueJay studios is always top-notch, too. As a matter of fact, just about every single kick sample I currently use is a BlueJay sample. Also, I've read good things about Drumkit from Hell but never tried it.
There's a few to get you started....