Definitely get the 152T. I just got a 172T after much thought and consideration, and I strongly believe that I got the best LCD money (in my price range) could buy. I'm no gamer, so I can't vouch for its pixel response (which seems more than adequate for me), but I'd have to artificially induce streaking and really look for it to find it.
Get the T because it has a DVI input. I don't know about other LCD manufacturers, but they definitely make a difference on the Samsung displays, the picture WILL BE NOTICABLY SHARPER! However, if you do not have a DVI input, nor do you care to have one, pick the S, which should be about the same display without the digital input.
One more thing, you can hook two computers to the T, one digital and the other analog, the S has one input.
Good Luck!