i have this one : http://www.wellnessfilter.com/Products/Shower.aspx
the wellness water shower filter, and when i bought it i did a lot of research and this was the best around... nowadays im not 100% sure its the best, but its def a very good one..
it appears more expensive,but consider the fact that you change cartridge much less often than other filters.
also, if you want to get the Cadillac of filters (although i have no way of knowing if the claims are true) listen to the interview of Robert Von on http://www.oneradionetwork.com
. he says his filter even takes out the fluoride, which no shower filter supposedly do...i cannot give you a link to his filter cause its not on the internet, you need to contact Robert Von directly to get one i believe... here is his website: http://robertvon.com/
good luck, and if you do try this filter out, please report!!