Since you're interested in CSS, I assume this is geared towards the web. I'd recommend "Designing for the Web" by Mark Boulton which dives specifically into web design.
The above books gave a bird's eye view without implementation. I'd recommend reading "CSS Mastery" to learn how to actually implement a layout. If you decide to use CSS frameworks, usually the documentation is enough when you have a basic grasp of CSS.
Most Photoshop books I've found cover using it for editing photos, not for graphic design. You can read these and learn a lot from them still. "Photoshop Missing Manual" covers almost everything about Photoshop, but it's a long read. I'm a huge fan of Steve Caplin's books "How to Cheat in Photoshop", "Art and Design in Photoshop", and "100% Photoshop". Graphic editors are still used for patterns, but I'm noticing a trend towards using CSS more for buttons/shadows/gradients now.
I'm mostly interesting in typography and color and this is a great read that covers all that and more.
[1] http://www.amazon.com/Design-Hackers-Reverse-Engineering-Bea...
If anyone is looking for something beyond just the Kindle sample, there are some links to sample stuff at http://designforhackers.com
Design Thinking by Ellen Lupton will help with concept development, sketching, and research. I'm reading Graphic Design Process by Skolos & Wedell right now and I would recommend that too.
If you ever want to learn more about advertising, creative ideas, strategies and concept development, read The Advertising Concept Book by Pete Barry, it's surprisingly big.