Circle II Circle - since their debut has yet to be released, there isn't a whole lot to choose from. I've hear four full songs from it, and I'd highly recommend purchasing it.
Evergrey - this a hard call. They're such a consistent band. If you're someone who has never heard them, I'd recommend "Search for Truth".
Mercenary - I, like most everyone else, would recommend "Everblack". It's their latest and their best.
Nightwish - I'm not a huge fan. I own "Wishmaster", and with the exception of "She is My Sin" I'm not impressed.
Pagan's Mind - get "Celestial Entrance". It is their 2nd CD and almost universally accepted as their best.
Redemption - similar to CIIC, they only have one CD out. I just picked it up but haven't had a chance to spin it.
Symphony X - another hard one to pick. To my ears, their two best CDs are "V: The new Mythology Suite" and "The Odyssey". Since they will be playing more stuff from "The Odyssey" live, than from "V", I'd suggest "The Odyssey".
Vanden Plas - my favorite by them is their latest, "Beyond Daylight". However, "A Far off Grace" and "The God Thing" are also very good.
GZ