An excuse to post more obscure, over the top, Danny feats.
Say hello to a short lived character named Bres. He was powerful enough to do this:
http://img.photobucket.com/albums/v330/CDTM3000/Avengers226_03a.jpg
http://img.photobucket.com/albums/v330/CDTM3000/Avengers226_03b.jpg
They had to resort to weakness exploitation, namely Iron weakness, to beat him.
And here's how Iron Fist dealt with him:
http://img.photobucket.com/albums/v330/CDTM3000/PowerManandIronFist113-ThePromise-21.jpg
http://img.photobucket.com/albums/v330/CDTM3000/PowerManandIronFist113-ThePromise-22.jpg
Danny threw his hardest punch ever, and knocked himself out in the process. This probably even beats the Helicarrier feat.
That muscle guy is Super Skrull, btw, in a disguised form. In the story, he regularly knocked Luke Cage around like a super ball, and displayed powers on par with a Superman clone (Which I can see him simulating with SS's power set.)
How many times has Venom beaten Carnage? And Venom, while formidable, can't hit anywhere close to as hard as Iron Fist.