Books for learning Verilog and SystemVerilog

Does anyone know of some good books on Verilog and/or SystemVerilog? I have just finished my first CPLD design by using the online training for Quartus, Verilog and SystemVerilog. Its working but now I would like to dig much deeper into the techniques. I typically learn best from books in a self-taught method.

Books like this are fairly expensive and I don't want to waste resources on junk or somethign that does not apply. As I search the web for these books it is clear that there are different aspects of these languages and different types of usage, such as for modeling, synthesizing, and simulating. Also there are different target technologies like ASIC, FPGA/CPLD. I am looking for CPLD (FPGA should be about the same) and specifically the synthesis and simulation. Writing test benches is also a vital topic. So if you have some recommendations I would really appreciate it.