Koge-Donbo*, of course, for creating Di Gi Charat. She's queen of moe imo, and draws really nice clothes- I think her and CLAMP are great in that aspect.
Junko Mizuno is just one of my favourite artists in general, she's got great style. Actually, I can't say I care much for the actual storylines of her manga lol, I mostly read them for the aesthetics.
Kishi Torajiro, as I've mentioned on another topic, draws incredibly alluring women.
On the flip side, Ono Natsume draws incredibly alluring men (well, the sort of men I like lol).
Asumiko Nakamura has a really unique and breathtaking style. I love it a lot.