I buy from both Newegg and Tigerdirect quite a bit, both are very good to deal with. AMD VS Intel...its pretty much personal preference...unless you are getting into some high end computing.
I work for HP...so I'm a bit biased...but I would stay away from Acer. The HP probooks are more of a business grade vs a consumer/home grade
I purchased one for my daughter when she went to college...and has had no issues with it.