Two pencillers could get me to buy a comic even if I had no particular interest in the character or didn't like the writer - George Perez and Jose Luis Garcia-Lopez. George Perez got me to buy Busiek's Avengers even though I disliked the writing. Garcia-Lopez got me to buy Atari Force even though I had no knowledge whatsoever of the characters or their universe. George Perez got me to buy Wonder Woman, a book I would never otherwise have dreamed of buying. (But see my "WRITERS" parallel to this thread.) Garcia-Lopez got me to buy Deadman, a character who only interests me when drawn by a superlative artist, like Neal Adams, or Garcia-Lopez.
A third artist I want to highlight is Terry Moore, who drew (and wrote) Strangers in Paradise. I'll be naming Terry Moore in my WRITERS thread also. His pencils (and scripts) got me to read a comic I would never in a million years have picked up, if all I had to go on was a synopsis of what it was about.
Finally, there's Tom Tenney, whose work on Force Works taught me to appreciate the 90s artistic spirit, which I needed help appreciating, because until Tom Tenney reprogrammed my brain, it was running a Bronze Age operating system. See pic.
How about you?
Romita Jr., Miller, Byrne, Golden, Dave Sim, Dale Keown, Mcfarlane, Perez, and Simonson were and are favorites.