I have added a small routine into the TeX filter. If possible it will attempt to render the graphic using Latex rather than the usual mimetex. This produces considerably higher quality output. If it doesn't work for any reason it will fall back to mimetex.
This depends on a number of items being installed on the server...
It currently only supports Linux (binary paths are assumed to be /usr/bin) and Mac (binary paths are assumed to be /sw/bin). The code could easily be adapted to support other platforms, but the binary paths are effectively hard coded so they would need to be added to the code.
I would appreciate if interested users could have a look and let me know if there are any problems.
(EDIT: This is in the 1.6dev / HEAD code by the way)