If you're getting a power rack, a bench to go with it would be a utility bench, like this
one.
That one doesn't have the leg attachment to do leg extensions or leg curls, but i haven't used mine in over a year since switching to compound movements. There's just no need for me. You'd just stick that in the rack when you need it and take it out when you're done. Because you'd be using the bench with the rack, you won't need to worry about if it supports olympic sets as it won't have any supports. You'll just use the powerrack to hold the weights.