Posters can serve a lot of different functions in limos. A big part of the reason what that is the case has to do with the fact that they can be used to personalize your limo and make it look just the way you want it to, and on top of all of that you can use them in such a way that they would block all of the windows thereby preventing anyone from looking inside and trying to spy on you in any way, shape or form.
You can find posters of your favorite bands and movies and put them up. Looking at them would make you feel like the space you are in is entirely your own, one that you would never have to compromise on at any given point in time. Since you would have more privacy in your Athens Kentucky limo due to these posters, you would have more freedom to as you please rather than to be judged by the people that are outside who are usually going to be jealous of you since they are walking around while you are riding in a really luxurious limo.
Seeing all of these posters can also be really inspirational for you. After all, these are your idols that you are looking at. You most probably grew up listening to them, and being able to see them during your limo ride can be just the thing that you need in order to make the most of this sort of thing. You can never have too many posters in a limo, there are just too many artists that you love and all of them need to be celebrated all in all.