Check out my rankings within each division by clicking on the links below.
Note: Results through Feb. 12, 2018.
LIGHTWEIGHT DIVISION (UP TO 155 POUNDS)
1. Tony Ferguson (22-3)
There's a very, very good argument for making Ferguson the No. 1 ranked lightweight in the world. He's up to 10 wins in a row, his latest an outstanding submission over Kevin Lee. This debate of Ferguson vs. Conor McGregor would be made easy if they just ... you know .. fought. That's what Ferguson is looking for now.
Next: UFC 223 on April 7, vs. Khabib Nurmagomedov
2. Khabib Nurmagomedov (25-0)
Oh my. Nurmagomedov may very well be the most dominant lightweight in the world, but inconsistent health has prevented him from proving it against the very top. Still, one can't help but wonder if this is the uncrowned king of this division.
Next: UFC 223 on April 7, vs. Tony Ferguson
3. Conor McGregor (21-3)
McGregor is on a money hiatus at the moment, with no firm timeframe for a return. His accomplishments speak for themselves and anyone who says he's out of his league against other lightweights is probably hating, but it's become impossible to vote him as the No. 1 lightweight in the world due to his absence.
4. Eddie Alvarez (29-5)
Alvarez didn't win a title at UFC 218, but it was a win for the ages. He spoiled Justin Gaethje's undefeated record and beat him at his own game, a back-and-forth slugfest. Just an unbelievable win.
5. Dustin Poirier (22-5)
Following his third-round finish over Anthony Pettis, Poirier has a full head of steam going at 155 pounds. He's well rounded, and beaming with confidence. A scary opponent right now for any one at the top.
Next: UFC Fight Night on April 14, vs. Justin Gaethje
6. Edson Barboza (19-5)
That was not easy to watch. Barboza saw a three-fight win streak get demolished in a demoralizing three-round loss to Khabib Nurmagomedov at UFC 219. He'll need a short memory to move on from this one. Just scrub that night from your memory Edson, and never look back.
7. Michael Chandler (17-4)
Chandler took care of business against Goiti Yamauchi at Bellator 192 in January. His only loss in three years involved a rare injury against Brent Primus. He's poised for a chance to regain his title in 2018.
Next: Bellator 197 on April 13, vs. Brent Primus
8. Justin Gaethje (18-1)
Gaethje suffered his first career loss at UFC 218 in December, but he doesn't fall out of the lightweight rankings because of it. There has always (and will continue to be) questions around how high Gaethje's style can climb, but he was very much in the fight against Eddie Alvarez, one of the most accomplished lightweights of all time.
Next: UFC Fight Night on April 14, vs. Dustin Poirier
9. Kevin Lee (16-3)
Although there was some controversy surrounding the end of the fight, Lee was still impressive in a first-round submission over Michael Chiesa on June 25. Big things potentially lie ahead for Lee as he hits age 25.
Next: UFC 216 on Oct. 7, vs. Tony Ferguson
10. Nate Diaz (19-11)
Diaz hasn't officially collected a win at lightweight since 2015, although his two fights against Conor McGregor in 2016 were more or less blown up lightweight fights. His hold on a Top 10 spot grows weaker with every month he remains inactive, as this is one of the most competitive divisions in the sport. That said, we doubt a "ranking" means much to Diaz at this point, who seems to be only hunting money fights.