matt, the arsenal hasn't so much grown as changed. i sold the 17-40 and am looking to sell the 28-105 on ebay. picked up the 24-70 which is just an awesome piece of glass. so i have the 24-70/f2.8L, the 50mm/f1.4 and the 70-200/f4L. the next lens purchase will not be for a while, but it will be the 135mm/f2L.
if you're doing any night shooting whatsoever, you need a tripod. the monopod will not get it done for exposures slower than 1/15 or so. you'll get all sorts of blur from trying to keep it steady. sorry, don't know anything about the vivitar tripods.