I have used sh404sef on many sites and by far is your best best for creating the best URL/DESCRIPTION/KEYWORD combination's - I promise you this, if you award me this project, I will configure sh404sef to work properly and control your url rewriting to it's fullest potential and give you the best crash course on what you need to know (not that difficult)
to be able to control the structure of your entire site. Let me know if you want to get together, and build it right. -Sandman