How often does the cover art influence your purchase?

I love book cover design. Does that make me lame?
Anyways, Penguin has published a series of its classic titles, with new book cover designs created by some of today's hottest graphic novel and comic artists. Some of my favorite artists have contributed, like Chris Ware, Tomer Hanuka, Frank Miller and Art Spiegelman.

Here is a flickr collection of the covers accumulated by Paul Buckley.

Image Credit: Tomer Hanuka

You can buy them from Penguin here. (You may need to Scroll left)
Here is a collection accumulated by Joe Kral of classic Penguin and Pelican covers. Notice the great design work and palette choice.

Image Credit: Charles Burn