Well that's a hard question... I love manga, some times more than anime :

I love CLAMP manga... I think my favorite is the tied story of xxxHolic/Tsubasa: Reservoir Chronicles :3

I just caught up with Yumekui Merry and I fell in love with the series. Right now Im reading Murder Princess, since I completely loved the anime version. I would still have to say Yumekui Merry is my favorite though, its just awesome.

I'd say it's Berserk. I don't really read a ton of manga and watch the anime most of the time if I can. Berserk however doesn't have one for most of it, so I read it instead. It's probably the only manga I've read that is still running and I'm up to date on.

Probably Naruto. It's the only manga AND anime I have ever made it a point to go out and watch the episodes for. 

I really don't read much manga but I've read enough to say my favorite all time one is Excel Saga closely followed by High school of the dead

Hmmm this is a toughie. My favorite manga comes to a choice between Mysterious Girlfriend X, Rosario Vampire, History's strongest disciple, and Dragon Quest: Dai no Daiboken 

I chose Mysterious Girlfriend X because it is an adorable romance/slice of life/school manga with a strange twist. The main female lead is able to read the mind of her boyfriend the main Male lead by tasting his drool. He of course is addicted to her drool and gets sick when he doesn't have a daily dose. It surprised her when she learned this before they started dating and together they go about life in their own little world.

I chose Rosario Vampire because I like Vampires and this was a great anime. Romance/superpower/school/supernatural genre I decided to read the manga and found as always that the manga was better and I followed it all the way. to a massive battle that blew my mind.

I chose History's Strongest Disciple because I love martial arts. This is a great martial arts/school manga that makes me laugh.

Last but certainly not least. I chose Dragon Quest: Dai no Daiboken because The original dragon warrior for NES was one of my fondest childhood memories. As my first RPG it generated a desire to expand into the genre of adventure games. This manga is a Adventure/fantasy manga that really touches on the classic spells and even adds a new ability to store magic in items for use as weapons. A young boy is raised on an island by monsters separated form humans living in peace from the time the demon lord died until he is reborn. When he is reborn all the monsters except a golden slime turn evil and rampage the island. 

I described what I thought were obscure Manga and left popular ones alone. These are my choices and all take the #1 slot in my favorites list. 

Since I've read only Soul Eater I guess I have to say that it is my favorite manga right now. It is actually pretty good and funny manga and I've liked it quite much so far. I like Soul Eater anime as well.

Well, my favorite manga is D. Gray-Man, the characters are just so awesome, and I always can relate to them :3 I would probably also call Tegami Bachi my favorite manga, but sadly, I have only one Manga of it at the moment :c

I also read a lot less manga than the anime I watch. However, when I do sit down to read a manga series, it tends to stick in my mind a bit longer. Here are a few of my favorite manga series:

Fullmetal Alchemist
Monster
xxxHOLiC
Pluto
HunterxHunter
Rurouni Kenshin
Angel Densetsu
Inuyasha
Kaze no Tani no Nausicaä
Yamato Nadeshiko Shichihenge
Jing: King of Bandits - Twilight Tales
20th Century Boys
Naruto
Shingeki no Kyojin (well, so far ^^)

My favorite manga is Bleach volume
thirteen with Kenpachi Zaraki.It is my
favorite manga because Bleach is my
favorite anime and Kenpachi Zaraki is
one of my favorite characters.

sop281 :  My three favorite would have to be legend of Zelda Oot, legend of Zelda four swords (still want to play the game!!), and Sgt. Frog

My favorate mangas are...

1 pokemon adventure

2 -i only read 2 chapters but my pick would be-hunter x hunter

Hunter X Hunter, without question. I actually went into a Barnes and Noble and bought volumes, 4-26. Freaking awesome. 

Other mangas I can't get enough of...

Berserk
Anything .Hack//
Initial D
My Heavenly Hockey Club
Ragnarok
Chronicles of the Cursed Sword
... And a bunch others...

My favorite manga would be Houkto No Ken or Fist of the North Star it is a very good manga if you are looking for a good manga I highly suggest reading this.

Oooh boy. Time for another Yuni-list! Because really, there's no way I can choose just one of the multitude I have read.

D-Grey Man, as odd as it is.
the Suikoden III manga (YES THEY MADE A MANGA IT IS GLORIOUS)
+Anima (it's short, but it's amazingly good)
Tegami Bachi
Trigun (WHY can't I find the rest of the series T_T)
Pita-Ten
Rurouni Kenshin
Read or Die
Kuro Gane
Elemental Gelade
Qwan 
and Gunslinger Girl.

I can't find the rest of the series for MOST of these, which makes me highly upset, since I have been looking for YEARS and I know they were brought to the US, I have seen them in bookstores...just...not since I started reading them and bought the first few volumes. :/

I don't really know what my favorite manga is but right now I am reading Angelic Layer and it is very good. I might actually go to the book store on Saturday and get a few more of the books. and later I might watch the anime.

I'm kind of surprised of two things. First is that I haven't posted in this thread yet, and second is why no one has mentioned Tonari no Kaibutsu-kun.  Sure, it's pure shoujo, through and through. But somehow, I was able to look past that. Still not sure how. But man, once I did, it was a hell of a ride. My Little Monster has to be the best manga I've ever read, and would be vying for number one anime of all time if there were more seasons to the anime. And man, does it need more seasons, as there is not a moment of this series that does not deserve to be put in an anime. Fantastic in all regard, a definite must for anyone into romance manga. (Or just in general.)

I can't choose just one, you should know this, Internet stranger. 

My favorite manga off the top of my head would have to be Berserk because it's the right amount of tragedy, butt-kicking, depraved, the-world-sucks-but-I-must-continue-on-regardless, brutal, "just...dude, no...why? Oh God why?" thing I've ever read. I don't care that it takes the mangaka like, three years to update it, I don't really care how it will end. I love what has occurred up until now and I'm gonna sit through it all till the very end.

The one manga that I will always have a fondness for will be Naruto because it was the first series I ever seriously got into, and if it weren't for a friend introducing it to me in 5th or 6th grade I probably would have gone through middle school and high school not paying attention to the medium and then what! 

Others I absolutely love are NANA, A Cruel God Reigns in Heaven, Deadman Wonderland, Bambino!, Food Wars!, A Bride's Story, Battle Royale, Mars, Onani Master Kurosawa, Ore ga Akuma de, Aitsu ga Yome de, and Pure Trance.

Any other fans?

I always liked the dbz manga.