The best fps of all time would have to be the Tom Clancy Rainbow series. My personal favourite was Rouge Spear and still is. Animations and graphics are still terrific 3-4 years later, although its starting to show its age.
Ghost Recon tried to be better but I still have a soft spot for RS. Half-life has poor sound and cartoonish graphics. I never really liked it. MOH is great but is not the greatest, but has the potential to become a true classic like RS.
Quake was also one of my personal favourites and I especially liked its evil gothic like overtones and hidden secrets. Loved blowing up those mummies heh.
When q2 came out it turned me off the quake series for life! too lame for me.
anyway thers my thoughts