RE:RE:MSN Stock ScreenerTMXmoney is another great site with all kinds of useful research applications as well.
It's got a great portfolio tool with multiple applications which I have used myself for some months now which helps me organize my watchlists, do certain research on those companies day to day, and keep track of certain end profit/losses. The portfolio tool works so much better than stockhouses for myself and is so easy to figure out, very user friendly. Ultimately it helps me organize everything very well.