for absolute strength in that plane and direction, the bench rules. the problem with it is not that it's not beneficial, but that because of the limited scapular movement, it's dicey in terms of shoulder health.
instead of benching for that strength, though, you can find ways to really overload a pushup--difficult without a partner and some gear, but totally possible. that would eliminate the primary problem with the bench.
as far as other capacities than strength, just look for push-up variations (of which there are a ton--just read my outstanding push-up article in this month's PM
!), standing horizontal pushing throws (e.g. with medicine balls), etc.