A little FiOS story -
Before reinstalling the WinXP Pro OS on my computer, my FiOS speed had always been blazing fast. Various speed tests reported 15 down/2.87 up.
*After* wiping out & reinstalling the OS, my downloading seemed unusually slow. Even though Verizon's FiOS own speed test showed 20.1 down/4.67 up (in January Verizon upgraded the speed), other speed tests reported "problems" and much slower speed.
A few calls to Verizon FiOS tech support was not helpful: The techs all agreed the WinXP OS doesn't need tweaks, or, other special settings in order to get max out of FiOS. Still, there was definitely something not right when it took several minutes to download a 30 meg file.
Then, in this forum, I found JoeSchmoe's link to Verizon FiOS optimization. After adding the registry hack I've noticed a big improvement: A 35+ meg file d/l'ed in 17.1 seconds. That's a bit more like it.
Thanks to JoeSchmoes for the tip.