Thought of a few more :
"he's a goner"
"look what the cat dragged in"
"it's seen better days"
"ignorance is bliss"
"your guess is as good as mine"
"procrastination is the thief of time"
"as useless as teats on a bull"
and my very favorite of all time--"if BS was $$ we'd all be millionaires"
