Makinosaka Shinichi
Lee (If you're game for some loli action he draws some damn adorable characters)
Inuboshi (ditto)
Rustle (Sorta the same as above, he has a very good style, but most of the stories are downers)
Digital Lover
Coelacanth
Maniac Street
NePaTa
Udon-Ya
Had to mention that last one again, as the art is always impeccable in everything done by him.
Here's from my personal list I posted on a similar post regarding artists I like, their art and stories are both good, and some I may have forgotten along with the newcomers:
Coelcanth
Homunculus
Hisasi
Wata 120 Percent
TakayaKi
NamaCreamBiyori
Meme50
Tosh
Dr.P
Gunma Kisaragi
Kensoh Ogawa
Osuzu Akiomi
JUN
Somejima
Nekomataya
Unagimaru
Jouji Mujou
Saegusa Kohaku
Otsuka Kotora
Heaven's Gate
Amatarou
Fujiya Honten(Thomas)
Pinvise
Bosshi
ED
Harumi Chihiro
TNC/Lunch
Jingrock
Cross-Fire
Distance
Takuto
Sameda Koban
Redrop
Takeda Hiromitsu (just the old vanilla ones I would suggest if you're looking into his style)
NiseMidi
Jouji Mujoh
Fueta Kishi
Naruco Hanaharu
Ungimaru
Yukimi
Napata
Saigado
Clesta
Kouchaya
Mogudan
Shinogi A-suke
Nishieda
Yarii Shimeta
Kima Grey
WireFrame
Kurokoshi You
Crank.In
Takatsu
Doi Sakazaki
My favorite h-manga artist would have to be Higashiyama Shou. Draws the best damn lolicon out there, very sexually arousing artwork and the stories range from just so ridiculous it is funny and cute, to actual complex "coming of age" stories.
In terms of "normal" stuff though, I'm definitely a very big Kisaragi Gunma fan, as well.
Hard to say. Really.
There are tons of incredible artist, and I can't really say that there is the best one out there.
Nevertheless, I would vote for Nakajima Yuuka and REAK.
[color=red]ED, Udon-Ya, Takuto, Nise Midi Doronokai.
My favorite H-manga artist for now. But there's a lot of great artist out there, just keep searching for it.
I dropped T2 (Tony Taka) from my list, he's good but I dunno why his artwork looks bit boring to me.