Front end vibrating like crazy over 50MPH?

I own a '05 Honda accord(front wheel drive) and the front end vibrates like crazy when going over 50MPH. So, thinking it was improper balance on the wheels I replaced all my tires and they did balance too. The problem is still there though and I looked at the suspension system myself and there seems to be nothing worn or grease leaking or anything on the suspension parts but I noticed the drive axel on the penger side seems to be loose a bit. It slightly moves1/4 of an inch forward and backwards from the links. Is this normal?