In all honesty, I do judge a book by it's colours. My favourite piece in this article is easily Batman #27. The colours are gorgeous. My thing is, if it looks like it could be Watchmen-esque colour-wise, it will probably look beautiful.
These colours instantly drew me in. They're bright and they just really capture your attention.
I find myself browsing the Previews when a new #1 is out, and more often than not, I skip it if the colours don't appeal to me in the thumbnails. It's sad, but it's true. Dull colours usually equals me thinking a dull experience.