Believe it or not, push ups did a lot for me. As long as you do explosive variations, some strength gains can be made. For example, I increased my max bench from 155 to 185 in two months of solid training. Although, after just two weeks of benching I was able to get my max to 205, and I feel that even with a bit of luck on a good lifting day I may be able to in fact do 210. If not this week, than definitely next week I'll be at 210 (don't chirp I'm only 150 pounds :'( but I'm working on bulking up so it's all good ). Moral of the story: Yes, push ups may indeed help your bench press and increase strength, but nothing is better for strength gains in the chest than the bench press. I made almost the same strength gains after two weeks of benching as I did after two months of explosive push ups. Increasing max benches at a higher weight is arguably harder as well, proving bench presses are more effective. (ie 120->140, a gain of 20 pounds, would not be anywhere near as hard as benching 180 pounds and moving up to 200 pounds) So try and do both as much as possible, but benching will get you stronger. Period.
