.Net (2.0, 3.0, 3.5), C#, Asp.net, Com+, GIS(ESRI Software), Management, Analysis & Design, Life, Trips, And more...
Two weeks ago, I asked Elad (one of the company founder) to order some technical books for our technical library. He told me to send him a list of books and he’ll order it. I wrote a list of technical book in vary subject in the development world (In .Net new technology oriented), the books were ordered by priorities. The next day, I sent him a list I made, and I told him that he can choose some books according to the list priorities. Then he told me “I count on your decision, the time I’ll spend on choosing the books costs me more than the books values”. Yesterday when I entered my office I had a pleasant surprise you can see it I the picture above. 
Conclusion: The cost of the books is nothing compares to the knowledge your developers achieve from reading them.