Motion blur on LCDs has been one of their weakest points for some time. Only in the last 2 years have some LCD models been released that utilize technology to reduce the amount of motion blur down to levels similar to that experienced on CRTs. I use LCDs for a variety of reasons, but I do miss the clarity/crispness of a CRT when playing fast paced FPS style games... Hopefully these solutions will continue to improve and become more mainstream.
Check out this page for some interesting details / comparisons:
This site is full of great information on the subject.
The main reason CRTs had such low motion blur is that the image persistence is much lower than that of a standard LCD (on an LCD without some of these newer technologies, each frame image is displayed for the entire frame duration).