The ones I've found that are good starting points:
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.