One recommendation would be to consider only using an immersion chiller with a whirlpool, such as described by Jamil Z: http://www.mrmalty.com/chiller.php
. I've been doing it this way at his advice for a couple/three years now and am very happy. I already had a 1/2", 50ft. MoreBeer chiller and just purchased their "Jamil" tube and added it. Wort temp drops like crazy that if your chilling water is reasonably cold (I live in Texas so I usually have to pre-chill), and after chilling, if you let the wort sit for at least 20-30min. the hops will all settle out and you'll draw off clear wort (except possibly the first little bit which I use for a gravity sample).
I have a nearly all Blichmann setup but even though I own one I don't use the HopBlocker or any other sort of hop filter. And obviously, I don't use my Therminator any longer either. Two addition advantages I see to going back to immersion is (1) you can truly whirlpool your hops and (2) you chill the ENTIRE wort down as quickly as possible. This is key for number of reasons not least of which is it helps proteins and other haze promoting material to precipitate out easier.
My two pence.