The first one is great. The texture and wispy wind effects make great art. The kind of grainy feel is given off and the grey tones complete it. This would make for an immensely enjoyable album cover. It's kind of mellow yet ominous at the same time.
The second one however is too contrasting. The focal point of the picture (the rider and the horse) is far to crisp in comparison to the rest of the cover. There seems to be much more different shades in the background then there is in the foreground, making it offbalance. The theme, also, is much overdone.
I say, for originality, and visual appeal, you should go with the first one. In my opinion, since many times I'd go to the cd store and buy random albums based on cover art, I'd be more compelled to buy a cd with the first cover rather than the second. Damn, I seem to have rambled on much too long here. o_o