It's well worth checking out the whole feature over at SFSignal, both for the gorgeous cover art and for people's insights into what makes for a good cover. But here are a few of the covers that people picked which jumped out at us. [SFSignal]

Shrapnel 3, cover by Stephan Martiniere. Writes gaming artistic director and concept designer Sparth, "Perfect sense of composition, perfect balance."

The Dream Of Perpetual Motion by Dexter Palmer (design by Ervin Serrano, Jacket illustration from Isifa/Alamy/Getty) As Orbit Books/Yen Press Creative Director Lauren Panepinto points out, that took a lot of time to put together. And it tells you so much about the book, including the time period and how awesome it is. She points to some other examples of elaborate/brilliant design in the SFSignal mind meld.

Finch by Jeff VanderMeer. Cover art by John Coulthart. Artist John Picacio singles this one out for its brilliant composition, and explains eloquently why the best book covers are about "becoming":

Becoming doesn't spoon-feed and isn't slave to the latest game of "follow the leader". It isn't the path of least resistance. It favors an audience that is active, rather than passive, dynamic of imagination, rather than static with nostalgia. It favors an image that evokes, rather than an image that crams the frame with every literal detail.

A Memory Of Wind, illustration for Rachel Swirsky's story at Tor.com, illustration by Sam Weber. Another one chosen by Picacio.

Picacio's own illustration for Frederik Pohl's Gateway, as chosen by Dave Seeley, who writes, "I loved John Picacio's Gateway, with his hallmark -surprising and clever- montage of figure and stuff (space in this case)."

River Of Gods by Ian McDonald, illustration by Stephan Martiniere. Chosen by self-confessed Martiniere groupie Dave Seeley, an architect turned book illustrator.

Hush Hush by Becca Fitzpatrick: (design by Lucy Ruth Cummins, photo by James Porto). Again, chosen by Panepinto. "I love how the image is so subtly colored towards the top. A really subtle touch. And the pearl paper is so nice. Such a spare design, it really was a breath of fresh air when I saw it."

Sharp Teeth by Toby Barlow: (design by Suzanne Dean, illustration by Natasha Michaels). Another Panepinto selection. Such a cool-looking image, it speaks for itself.

We were thrilled to get to hang out with Picacio at WorldCon, and see his work up close in the artists' exhibition room. We asked him what his philosophy of SF illustration was, and he said:

I’ve never thought about my work with any driving philosophy behind it, really. I just react to the things I see in my head, our chaotic world that seems to be more chaotic every day, and to the genre manuscripts that I’m fortunate to illustrate on a daily basis. But hopefully my images connect on their own without me!

His cover illustrations for The Margarets by Sheri S. Tepper and Time's Child by Rebecca Ore were both named as finalists for the Chesley Awards recently. His website is here and you can keep up with his work on his blog.