I am fascinated by football helmets and uniforms. I study them like some people I know study the dresses movie stars wear at award ceremonies. Like any enthusiast, I have my opinions on the aesthetics of uniforms and helmets.
In my opinion, these are probably the two best helmets in all of football:

I’m not crazy about the black pants for the Bengals–I almost always prefer white jerseys with white pants–but otherwise I think these are pretty good. (Interestingly, the Ram helmet with yellow horn was the first football helmet design ever.)
Apart from white-on-white, I usually don’t like the same color jerseys and pants–teams like the Chiefs, Texans and Cardinals will wear all red, and they look like they are in their pajamas. I did like these old Buffalo Bills uniforms, though I would prefer it with a white helmet.
The absolute worst uniform in all of football is the Tennessee Titans’ current one. It is a total disaster, although this mess the Jaguars wore (against the Titans even!) is pretty bad, but it was only an alternate.
I am also a big believer that you can’t change your uniform once you have success with it. The Rams won the Super Bowl with their yellow horn helmets, then changed them to an awful gold color, and haven’t won since. They did lose one to the Patriots, who are now stuck with a pretty bad uniform that they have enjoyed tremendous success in.
At the college level, everybody gets new uniforms all the time now, thanks to the influence of the Oregon football team. Oregon wears a new combination every week, and I have yet to see them find one that is good, although these chrome helmets look kind of interesting.
In general, I find most college uniforms to be stupid. I do like these all-grey uniforms that West Virginia and a few other schools have done. Strangely, my team, the Ohio State Buckeyes, has not worn one of these even though grey is one of their traditional team colors. Speaking of the Buckeyes, their regular uniforms are some of the best in the sport. These alternates, which I call their “Christmas tree ornament helmets”, are weird but interesting.
Probably the best helmet/uniform combinations in college football are USC, Ohio State and Michigan State. I also loved these camouflage uniforms that Army has worn a few times.
What helmets and/or uniforms do you like?