re: Poker & Medium stacks avoid big stacks it's -EV?
I think the best way to play against a big stack is to use caution, but also be aggressive when you have strength. Of course, as usual, it depends on how the big stack is playing; if he/she is in every pot; raising more than not, and generally being a bully, then yes you need to play back at them to stop such behavior. but if they're playing tight, only raising w/ premium, and really just not taking any big risks, then perhaps it's better to open up your range a bit, try to three bet and steal as many pots as possible.
The reason i love poker is that there is no 'right' way to do anything in this game, so ultimately it's up to you.