I thought this was an interesting read. Turns out what most people figure to be a 3-4 really is a variation of a 4-3 defense. I personally am a fan to running hybrid schemes in order to make best use of your talent and keeping opposing offenses off balance. Notice what this guy says about Bellicheck, Parcells and Capers. Hopefully you all will find this article interesting as well and I can't wait to see your comments.
http://www.profootballweekly.com/PFW/Features/Super+Bowl/2008/wwhi013009.htm