Wow. You've got a lot here and a lot of variety as well. Since I really like colorful pieces, I love that so many of your pieces use a lot of different colors. I'm not really sure which stuff you'd like me to comment on most, but I'll say what definitely caught my eye is your wallpapers. I love a sort of surreal/spacey/fantasy look and, while you do that in some of your other graphics, it really shows up in your wallpapers. There's absolutely no doubt about which of your graphics is my favorite--
it's this one. Of course, that one has a leg up in the first place because I love dragons and dragony things, but it also has a great colorscheme, effects, and oozes a sense of drama. I think the banner version you made of it is okay, but it loses a lot of its epicness in the shrink, and the text gets so small that I feel like it might as well be removed. But the wallpaper is fantastic.
Your other wallpapers are really cool, particularly in the contrasting scenes they present. I love the greens in the next one down and the starry reflection on the water. I will say I was a little put off by the visible outlines around the tree and mountains at first, but I think the image is stylized enough that it works. For the next one down, the flooded pyramid scene is obviously really striking, but what draws my eye is that kickass sky.
So yeah, there's some really awesome stuff here and the style that you're using in your wallpapers is one that I definitely find really appealing.