I am currently just watching the one, One Piece. Although, not too long ago I was watching like four at once, but it got too awkward.

I'm watching er.. 6. I have plenty more to go too, trying hard not to make it 7+.

I am watching around 20 anime series. Here are a few example's :
Bleach
Full Metal Panic, The Second Raid
Suzuka
Futakoi Alternative
Kidou Shinsengumi Moeyo Ken
Mar
Da Capo Second Seaon

I'm watching One Piece, Naruto, Vandread the First Stage, and Bleach. I'm watching kgne, Tenjho Tenge, Ichigo 100%, and Gundam Seed again.

I'm watching Gundam SEED Destiny, Naruto, Bleach, Tsubasa Chronicle and Full Metal Panic! tsr...i think that's all

3 I think...

HOLY heck!! 20+?! One is enough for me, although I am following so many other comics/TV shows, so I don't really have time for anything else. My hat's off to you though, you're now my new anime-watching idol hero.

I'm currently watching 3 animes. Inuyasha, Bleach, and Gundam seed.

I am watching
Bleach
Gundam Seed Destiny
Tsubasa Chronicle
Trinity Blood
Full Metal Panic, The Second Raid
and a couple of other animes but they are already finished and i have all the episodes so I do not count them unless the series is still airing

a few

Bleach

Please Twins

Ikki Tousen

Galaxy Angel Z

Full Metal Panic

Read Or Die TV

just for starters anyway, there are others that i have started, mainly just via d/l but i havent gotten round to gettin the eps cause i havent had the chance to yet ^__^;;

I'm watching Leo the Lion, Lupin III and Cowboy Bebop (again!).

Just Monster at the moment. I tried a few other series like Rozen Maiden, but they were pretty bland. Not that Monster is that great, but. . . .

hmm, let's try this ...
Bleach
Gundam Seed Destiny
Trinity Blood
Fafner in the azure
Tsukuyomi Moon Phase
Full Metal Panic
Last Exile (more like planning on finishing it one day)
Ghost in the Shell (same as above)
so 6 for real and 2 sorta.

Full Metal Panic The 2nd Raid

Right now 8, but I got some more coming...

Hmmm. Not that many actually. Just what's on the TV. I think about 3 or 4. ^_^

Bleach, Naruto, Suzuka, Shuffle, Gundam seed destiny and full metal panic - the second raid. these are the stuff i'm watching which is still being air'd

I'm still watching Rurouni Kenshin and Full Metal Alchemist. Nearly finished them both though.

I watch one at a time. (finished series only)
I don't like to watch ongoing series. ,If I do, I have to wait for next episode release.

i'm watching....

Gundam seed Destiny
Turn a Gundam
Monster
Yakitate Japan!!
Aishiteruze Baby
Tsubasa Chronicle
Air TV and Movie
Turn a Gundam
Prince of Tennis
Mizuiro
Samurai Deeper Kyo
Legend of the Condor Hero
Black Jack
Violinist of Hamelin

Still hoping for a few more that interest me a lot. Any suggestions?

Well, i am watching 6 ongoing series. d.c.s.s. , GSD, Tsubasa Chronicle, Shuffle, Trinity Blood, Bleach.
I also am dling NGE, Noir, Sister princess repure, and Onegai Teacher.

I think it's 4.... hmmm bleach, naruto, .... samurai deeper kyo and wolf's rain.

I still watching Bleach, Gundam seed destiny, Full metal Panic 2nd raid, Naruto, ichigo 100%, and I forget the other.

Just finished watching GTO, Full Metal Panic, and Paranoia Agent. Now watching whats on t.v and what i own like Inuyasha, Scryed, Samurai Champloo, Full Metal Panic Fumoffu, and Tenjho Tenge.

-> Hmm...let me think:

Anime series
- Saber Marionette J to X
- Full Metal Panic: Fumoffu
- Initial D 4th Stage
- Azumanga Daioh
- Gundam Wing
- Tenjho Tengue
- Steel Angel Kurumi 2.0

Manga
- DearS
- Negima: Magister Negi Magi
- Boys: Be
- Hanaukyo Maid Team (too bad, the distributor was shut down {Studio Iron Cat})
- Imperfect Hero
- Yotsubato/Yotsuba&

Waiting for...-> Wangan Midnight manga, Goldenboy manga, Takara Transformers anime, and Negima anime. (: