if you do mf, USE it (!!)
put it into your occulus or into your ali baba,
put it into your sorc armor/helmet if you think topas dont work (difference 1% lol)
put it into your shield if you dont use rhyme
sell it to the right buyer in trade channel, its less then shako, but its still worth a lot,
especially if the person NEEDS ist
make delirium helmet if you use a frenzy barb/zeal-pala/melee assassin
check battle.net for other runewords with ist
get another ist and create a gul rune
put it into your cube with arrows to get some bolts
just some ideas i had