Personally, I'm the guy in Magic who makes you laugh, and then beats your face in (not literally, people! :)
Glarescape? That was me. (People who don't play Magic, Glarescape is one of the Most popular decks in the Format). Mind you, it was an accident, but nonetheless. I love the way Magic has a massive cardpool and that no card is "the best", (Though Umezawa's Jitte is annoyingly close...). The game is not only decided on the deck, but the player of the game. Even if you took a copy of the World Champ's winning deck, but didn't understand how to play it, you'd be crushed. Also, the rarity of cards is so much easier than other certain games (We got 3 rarites: Common,
Uncommon, and Rare! 3!). Oh, and our shiny cards have nothing to do wth rarity. How cool is that? (Slowly trying to get shiny versions of all my cards so I can have a shiny Pro Tour deck! That would be Wicked!)
Yu-Gi-Oh is...interesting...in that 1. You don't have to "pay" for your first Creature (Or is it monster? I get confused.). And Magic and Trap cards are free? Meh. It's got some cool stuff to it, and I totally respect the game, but I simply don't like the gameplay. In Magic, you have resources (lands & other mana producers) that you have to tap (drain of their energies for the turn) to play Creatures, Instants, Sorceries (Like Traps), Enchantments and Artifacts (kinda like Magic in YGO). The only thing that's free is a 1 land a turn drop. But you have to have the lands in your hand first. Also, lands on produce certain color(s), so you can't use a Mountain to play a raging goblin one turn, and the a Plague Beetle the next. (Red, then black).
Pokemon, I'd have to say,has great gameplay. At least, the original game did. That's not to say it's not all still good, but I started when it did. I still have my Charizard deck (Yeah, the Orignal Charizard, people). And even then, I made my deck a Unique Charizard deck. It's not the same build other people use. It's a relatively good and unique concept.