I could name a bunch of examples, but I find it telling that they're almost all from Basic or 1st Edition products.
I love 3E, but I'm simply not as drawn in by the artwork. Don't get me wrong, some of the artists they have working for 3E are excellent, but the style is far more "comic-booky" than it was in previous editions. Comic book art has its place, but I don't think it's in D&D.
The older style of artwork may even have been technically "worse," but it was far more evocative, felt far more fantastic to me. Basic, 1st, and occasionally 2nd all had pictures that really grabbed me, that made me wonder who the people involved might be (i.e. the Emerikol the Chaotic pic in the 1st DMG), or made me wonder what was going on, or even inspired story ideas. Third edition art--again, while often of good quality--makes me instinctively look for word balloons.