agressive toward people

I would stop free feeding him for one.  It really is not healthier (in nature, dogs are not grazers, like horses, but eat their fill when prey is available), plus it can cause problems.
 
Why should HE decide when he gets to eat?  YOU are the leader, that is YOUR job.  He has no need to have control over the resources.  I would suggest reading the feeding instructions on the food bag, and splitting the daily amount into 2 meals.  Before he gets to eat he must do something.  Sally has to "down" the entire time her meal is being prepared, and wait for her release word, which is "OK" to eat.  Even if the bowl is right in front of her face, she is not to touch it until we say.  We even have "spelling tests" where we say words that SOUND like OK, but are not the actual word to hone her listening skills.  Why?  Because this just establishes that as her leaders we have the say as to when she eats, how long she waits for her food, and how much she gets.
 
I would also restrict this guy's furniture privilages.  Is he crate trained?  If not, I'd do that, because it will help.  Furniture are prime resources and it is not his place to decide when he gets to use them, it is yours.  When you are not home, crate him.  This will let him know that the run of the house is not his to take.  When you are home, teach him "off," and simply do not allow him on the furniture for a while.  If his behavior begins to improve, he can come up on it with invitation ONLY.
 
I know that it doesn't seem like stuff like this would matter, but to a dog, it does.  Sally has no aggression issues at all and I have seen a huge change in her attiude, and she has become less fearful.

thanks, i think ill follow your suggestions about feeding times.  it makes sense. 

I  have read through the entire 5 pages of messages on this thread - and I just want to add my comments and personal experience with an "aggressive" dog.  I've posted recently (but not in a while) about my aggressive Molly.  I posted that we had a behaviorist evaluate her in April and she wanted to do a three-week residency program, using a remote collar... After much discussion, research, thinking, etc. we have not done this. 

We did institute the things the behaviorist suggested - keeping her on a short leash so we can grab her if needed and not get bit, not letting her on the furniture or bed, making her sit or lay down before she gets her food, toys, etc.  In the 6 weeks or so since we've done all this, she has improved so much!  No one has gotten bitten since mid-April, when we started all this!  Molly will still do her growling/thrashing about in a few instances - if she doesn't want to be picked up, or if I'm cleaning her eyes/face.  With the cleaning issue - I'm doing it every single day now and at first she growls, but then stops when she realizes her temper tantrums aren't going to get her anywhere!  She still exhibits some resource guarding, but is improving in her reaction to us taking something away. 

Six weeks ago, we were ready to ship Molly off for three weeks, thinking there was no way we could handle this ourselves (this behaviorist said her aggressiveness/biting didn't make here a candidate for group OR private lessons).  But these simple steps that so many on this thread are advising really make a difference!