There's several highlight blow outs in some of the sky images and why is the sky darker than the land / foreground...looks like to strong grad filters too me. Nice colours, but some of the scenes look like there's false colours added from the ND grads colour casts. The scenes are nice and dramatic, but many of these would fail RPS judging (or degree level photography portfolio judging) due to the exposure issues I've just mentioned. There's bad flare in one shot and another has split boulders in the fore ground, it's important not to split any in half at the edges of the frame. These are very nice and colourfull images, i'm sure they sell well to punters. Especially to the framed print crowds, but really wouldn't impress anyone with a qualification in photography.
I almost forgot to ask, what's your website URL?
GMC has some wonderful images here: http://www.canonrumors.com/forum/index.php?topic=4624.msg355920#msg355920
Actually, I understand what GMC is saying. Your ND and grad filters are causing color shifts. You may want to consider changing to more expensive filters, if you so desire.
Now, having said that, photography is an art... so there is no rule why color shifts are bad... that is why some deliberately choose to use the 'wrong' white balance and others are able to produce colored IR images (just saw a whole article devoted to that in Landscape Photographer)...