My favourite is whirlpool - the water looks good and fluid, and I like the standing stones as well.

The lightning one reminds me of a piece from Disney's Fantasia (the original version), wherein Thor is throwing lightning bolts around for some reason.

Dark Chaos is good, and I like the glowing eyes (any destructive firey demon worth its salt has to have glowy eyes), but something doesn't quite seem right about the lightning. The hand of fire looks like it should be very bright, but it doesn't seem to affect the shadows - it still looks like the main illumination is from the front.

Hmm, that reminds me. I got asked for permission to use one of my photos in a book about a library restoration project. Now's about when the book was supposed to be printed, so I'll have to follow up on it and see if they used it in the end.