Classic: If capcom makes sequel to megaman, then god bless if it's this series, i really had a lot of fun with the classic series, specially MM7, I like the setting, I like the art style, I like the music, and it isn't a complicated mess, perfect for some simple fun.
X: I Know X kind of saved megaman, and that litteraly everyone in the planet worships this game, but i personally don't like it, Some stages look bland, The bosses are innecesarelly hard, and i really don't like how the game controls, This said, i credit the game for having a super cool soundtrack.
Zero: I only played Zero2 but i can tell you, this game is brutally hard, i can't give many details because i never got past any maverick thingie because all of them were too hard. ZX: This one's pretty nice to play i only played the first game and got past the first boss but it's really fun!
Battle Network: If my Profile Pic, My username, and MM8BDM binds didn't tell you anything, I Love this series, 5 being my favourite out of them all. i like the battle system, i like the art style, i love the setting, i love the characters and i certainlly love the music.
Star Force: it may not be battle network, but it's just as fun as battle network, and i like how folder building isn't limited to what chip codes you have thanks to the new battle system, SF3 is the best.