Around the time..Im gona list a couple for each since most fought eachother to decide the best but there were a couple big names each division..

147 : 1999 Trinidad and Oscar In 2000 oscar lost to mosely and beat gatti only fighting twice that year so i would have mosely as best in 2000

154: I would have Fernando ruling 99 having beat quartey and winky and bieng undefeated..
And i would have tito riegning best in 2000

160: Probably hopkins..But thats a bit of a bad one since there wasnt loads of great fighters at 160 at the time and hopkins didnt prove himself until 2001 against holmes, tito etc..