I am researching load speed services and or programs for my company. I've tried a few of the programs that are out there, and a few of the free online load speed checkers as well.

Can anyone recommend a solid online service or program to monitor load speeds, speeds based on user connections (dial-up, cable, DSL, T-1), etc...

This is for a very large retail site, so I am looking for something a little more sophisticated than the free services out there.

Any recommendations would be great!