I've had a couple emails in recent times from people who like my work and seem to think I'm among or even actually the best pixeller using Game Maker. I assume these people have never seen DarkfalzX's work. I think he focuses more on GBA and DS coding now rather than GM but he's a better pixel artist than I could ever hope to be. Certainly professional commercial quality. His character spriting and animation is generally superb as are his background and tiling work too. You guys really should take a look at his gallery at Pixel Joint to see what I mean. Honestly despite my differing preference in style (I'm not so keen on cutesy fantasy stuff) I wish I had even half the talent of this guy.
Check out some of his work at DarkfalzX's PJ Gallery