Hey all...so sorry about not replying right away. This past month has been pretty crazy for me: finishing clinical affiliations, starting classes, and I had a bunch of new clients all at once (when it rains it pours I guess!).
As far as lifts go, the "standard" of strength is 500, 400 and 300: a 500 pound deadlift, a 400 pound squat and a 300 pound bench press. Whether or not you can actually hit numbers like that, it does give you a decent idea of around where your numbers *should* be based on muscle output and amount of muscle being used. Your most-muscularly involved lift, the deadlift, should be heavier than your squat, followed by your bench. If you're not (perhaps your bench is heavier than your squats, or your squats are heavier than your deads), there could be a number of reasons why: a "true"muscle imbalance, a flaw in your technique, or the way that your body is built in terms of genetic muscle distribution, length of levers, etc. In order to understand and know your muscle imbalances, there are a number of *tests* that you can follow (this is a nice one, with links to other tests:
Muscle Strength and Balance Checks) but even this may be flawed since your form could be off when you perform these lifts (yes, even in a machine based on positioning and use).
The only way to *really* know is to have someone qualified to evaluate you. The vast majority of gym trainers can't do this, unfortunately, and wouldn't even know where to begin, making this difficult. A good ortho/sports physical therapist can, as *should* athletic coaches and trainers.