I agree with WD on squatting. I do legs and chest the same day and don't find much hindrance. On the free weights vs machines question, unless you are forced to choose one over the other, why choose? Variety is important to continued progression, IMO, so having both is the best possible option. I like machines for things like laterals for delts, and butterflies for chest, because using free weights for these irritates my shoulder joints, which took a beating from too many years as a banquet waiter (carrying many heavy trays full of dishes every shift). Also, on some exercises free weights fail to provide resistance through the full range of motion, such as on preacher curls where the bar is moving almost horizontally on the top third of the movement giving the biceps no resistance at all. Most curl machines don't have this problem. I would stick with free weights for the basic movements at the very least, however.