Case busting is hardly ever rewarding, just buy your favorite players in the off-season, if you must bust something buy a $100 rookie premier case from 08 you get 700+ rookie year cards and a auto (on average). Anything else buy your lube first you'll need it when your done.
If you insist on a case just look for deals, 2004 & 2008 are the better years IMO.....The best bang for your buck comes from doing your research, start on ebay search for product, search completed listings, find sellers on ebay, go to their websites, email or call them to negotiate a lower price.
My advise is wait until 2009 exquisite football comes out and buy singles when everyone is trying to recoup from their loses and get deals from those who had big hits and don't care about the $50-$200 stuff. It all depends on you though and what you collect and what you like.