http://hutchinson.belmont.ma.us/tth/
I consider this one to be the best. (I've tried almost all of them.)
It runs VERY quickly, and in my opinion gives the best results.
I've got a short Web page on tth, giving a quick intro and some
tips. If you are interested, go to my general LaTeX page,
http://heather.cs.ucdavis.edu/~matloff/latex.html
scroll down to the section titled "Programs to convert LaTeX to
HTML (not a complete list)," and click on the tth link.