All cards work the same,they're all made of paper.
I don't agree, a card finish is very important for any flourisher, plus not all of the cards are equally firm (Bicycles feel like warm butter compared to Tally-Hos). Somebody said Wynns above, but I don't like them because they don't last long (a little humidity combined with some dirt from falling makes them pretty much unusable for any kind of rotation-based flourishes after only a few days), and fanning them without fanning powder is a lot harder than I would expect from a brand new deck. They look nice, but that's about it.
In my opinion, the best cards for flourishing are Tally-Hos. They are firm, look nice, linoid finish is very comfortable to handle and they are extremely durable (they fan nicely even after two weeks of extensive usage and abuse). Also, you can get them for 3 bucks per deck, even less if you buy a brick or so (check out some quantity discounts at T11 and other sites). I practice XCM for over 2 years and no matter how many decks I try out, I always get back to Tallys. Sure, all the cards are made out of paper and you can use any deck to perform some Charliers or the Sybil, but trust me, you won't have any regrets with Tallys.
As for the flourishes, I strongly recommend you get Andrei Jikh's Genesis volume 1, since it pretty much covers the basics of cardistry. After that, you should probably check out either volume 2 of Genesis or Jerry Cestkowski's Encyclopedia of Card Flourishes. Somewhere in the meantime you should learn 5 Faces of Sybil and after you feel comfortable with a fair amount of seen moves, it's all up to you. Dan and Dave have some nice simple and intermediate material on their DVDs System and Trilogy and you should also check out The Wire on this very site.
Oh, and, welcome to the world of card flourishes, hope you'll enjoy it as much as we do!