My favorite is easily Megaman Batle Network. It's the one I grew up playing with and I loved the storyline of all 6 games. But I love all of the series.

I say Megaman Battle Network, specifically Megaman Battle Network 2, Megaman Battle Network 3, Megaman Battle Network 5 and Megaman Battle Network 6. The storyline in 1, 2 and 3 is amazing, 2 is well developed and 3 really has a lot of epic stuff to offer, especially a fun but sometimes challenge. Starforce is also good though.

For me, it's a blowout.  Megaman Zero, NO argument.

Megaman Zero gets my vote, but behind probably is X.

The original series, and the Mega Man X series. I can't decide which one I like more. They both mean equally to me.

Mine is Megaman x by far.

Mega Man X will grind them all

I voted for Mega Man X.

Although I'm kinda noob in Mega Man games, and only have played games from the classic series and the X series, which seem really awesome. I didn't like the Battle Network (NT warrior) anime that much, but the games may be really good with these battle chips or whatever. I don't think that I'll like it more than classic or X however.
From what I've seen from Mega Man Zero, it is also a very good series and I know little about Mega Man ZX, while I have no clue what Mega Man Starforce is and Mega Man Legends doesn't look as good as the others.

It may be late, but I think I'm really getting into Mega Man games. ^^

Ryore: HA-FIVE Mega Man X ROCKS

My favorite Megaman series is between the Megaman Zero series and Megaman ZX series. I like them both because there stories take place years ahead in the future, and well they portray a(n) interesting new out look on the Megaman universe. In addition I also like there two series because the bosses seen in both are by far the most creative with the way there appearance is and their abilities. 

While I love the X and Zero series I also love the Battle Network and Classic series. So those 2 would have to be my favorite. Their more kid friendly and fun inducing to me.

My favorite Megaman series Television wise would be Megaman NT warrior, and my favorite Megaman series game wise would be Megaman Zx and Megaman Zero.

I really love both Megaman zero and Megaman X, X did come first and allowed Zero to exist in the first place... Not to mention all the game play from Zero is partially based of the original Zero game play from X4, So I'm going to go with X on this one although I love Zero's story more, X is the one that started it all for me too. Enjoy your time, You only get so much.

My favorite is the Battle Network series. I just enjoy the stories of the games, the way the gameplay works, & the added features each latter entry in the series brings to the table.

My favourite is definitly the X series. I love the innovation it brought to the franchise.

Mine is Megaman Battle Network. I loved Megaman NT Warrior as a kid (and I still love it) so naturally I loved the game even more. The 4 or 5th game is probably my favourite and the storyline of all six games and the gameplay of it too. I loved the battle style of it, it was completely unique too any other Megaman game. The features of the game are different from all other games so essentially I was playing a whole other game. It's still today one of my most favourite games on the GBA next to Golden Sun.

megamanmaniac : Hi five bro!  My favorite Megaman Series is also Megaman Battle Network.  I grew up playing this, and sunk dozens (maybe hundreds!) of hours into Megaman Battle Network, Megaman Battle Network 3: Blue Version, and Megaman Battle Network 5: Team Colonel.  I felt that Megaman Battle Network was a good start to the series, but is also the weakest in terms of gameplay, diversity in environment and enemies, and difficulty (it's super easy).  Megaman Battle Network 2 was a jump in the opposite direction.  It had greater environments, a better battle system, better bosses, and much greater difficulty (probably the hardest I've tried in the series).  Megaman Battle Network 3 (either version) is my favorite of the series, and the most balanced in terms of difficulty and battle chips, and really did a great job with the map of the internet.  The bosses were fantastic, especially Flameman, Serenade, and Bubbleman.  I loved the CrossSoul system of Battle Network 4, but was disappointed by the whole darkchip thing.  I really felt that they didn't make the most of the concept, and brought the gameplay down a bit, despite the CrossSoul system.  Battle Network 5's liberation missions were fantastic, in my opinion.  I feel that that's the "Dark Horse" of the series, and is underrated.  The ability to play as other Navis was a serious bonus.  Also the darkchip fusion system made the whole dark chip system better.  But it still didn't quite have the finesse of Battle Network 3.  Battle Network 6 ended the series on a high note.  Capcom brought the series back to what it did well, and did quite a fine job of it.  One may also make a case that this is the best in the series, in place of Battle Network 3.  This is quite possibly true.  But Battle Network 3 is my favorite, since I played so much of it in my youth, mastering the techniques and program advances, and countering Gutsman time and time again to gain bugfrags for the bugfrag chip trader in the Undernet.  It was a good grind.

My favorite Megaman series is between the Megaman Zero series and Megaman ZX series. I like them both because there stories take place years ahead in the future, and well they portray a(n) interesting new out look on the Megaman universe. In addition I also like there two series because the bosses seen in both are by far the most creative with the way there appearance is and their abilities.