The only parts that would benefit from the extra fan up front is your HDD/SDD. Try it without a case fan mounted up front and monitor your temps. If your parts get too hot, then consider getting another fan. Great article on fan placement and cooling effect: http://www.bit-tech.net/hardware/2012/02/10/the-big-coo...
I got impatient and just ordered one...lol Not that of a price increase compared to what I've already spent anyway.
In addition to cooling the HDD and SSD, I heard it also helps with the intake of air into the case which improves the airflow and a lot of reviewers recommended that I get one so...can't hurt to have one I guess.
Not to mention I may be doing some OCing on the new 3570k.