I appreciate that Dungeons & Dragons 4th Edition books give credit to artists on each page. It was sometimes hard to ascertain, prior to 4e, which artist was responsible for an illustration. I like to look at fantasy art and enjoy finding new artists.
I like the Time Bender paragon path illustration by Jim Nelson (page 96, Player's Handbook 3). The psion class aspects don't speak to me. I would prefer art without crystals and a halo but the subject matter can't hide the core elements of Jim's style that grab my attention.
D&D 3rd edition books sometimes show the artist name (page 85, Player's Handbook v.3.5) and sometimes do not (page 150). Most of the time, such as Lars Grant-West, you can discern the artist. When you can't figure it out, those are the times when it can be really frustrating. First look for artist initials within the art and then turn to the credits (usually page 2) where you hope that only one artist in that book has those initials.
The Basic Set claims illustrations only by Larry Elmore and Jeff Easley. Usually it's easy to tell them apart until you find a dwarf (page 45) signed "E". I'm pretty sure that's E for Elmore. I prefer to avoid guessing games.
Many thanks to Wizards of the Coast for making my life easy by clearly indicating the artist name on each page. Please continue this tradition when designing page layouts for 5th edition's D&D Next books.