Stylin' with CSS by Charles Wyke-Smith - its mainly a (good) CSS book but gives enough hints at good design so you don't go overboard.
Handcrafted CSS by Dan Cederholm with Ethan Marcotte - again CSS tutorial with emphasis on good design with CSS.
Once you get the handle on those (or before hand) check out the great examples in CSS Zen Garden. ( http://www.csszengarden.com/ ) Something you can pick apart and analyze. The cool thing about ZenGarden is the HTML is always the exact same file it's the CSS and graphics that make the designs different.
Beware web design books that concentrate purely on web design - some of them are trying to be too artsy and cutting edge, look inside the book before buying... also some may be specific for templates in WordPress, Joomla or some other CMS.
For web design, here's my list: http://hn-books.com/#BC=0&E0=2&EC=1&FC=0&Q0=...
Note that if you like, you can sort by knowledge level and book format.
I used it (to some extent) to learn both, but still haven't grasped how to work with CSS layouts and build a real web page. I don't blame the book though - I blame my laziness.
The online version is free to view, and there's a paperback edition available for purchase.
Here are two resources that I read daily and provide a lot of good juicy material:
http://www.smashingmagazine.com/ http://webdesign.tutsplus.com/
The Elements of Typographic Style by Robert Bringhurst
Non-Designer’s Design Book by Robin Williams