I have a grad degree in algorithms and the best book on algorithms is Cormen et all's "Introduction to Algorithms". You will be able to keep this book around forever and you won't outgrow it that easily. Definitely the best book on algos and an excellent reference.

http://projects.csail.mit.edu/clrs/

Google Books: http://books.google.com/books?id=NLngYyWFl_YC&dq=&pg...