Needing air or not is truly a personal decision based on your physiology, your location, and how you will use the car.
I will use the air when we are making a long highway run and don't want the top down for some reason, when it is raining and hot, and with the top down if it is hot and we are sitting in stop-and-go traffic. The average usage is 5-6 times a year.
If there is an issue with resale it is going to be finding a buyer, since many people will hesitate, just as you are doing. The car will sell for less, but you are also going to be buying it for less, so that part is a wash.
Do you always use the A/C now, or do you tend to put the windows down? Having the top down will make it less necessary when driving, but more necessary when stopped.
Sky NA 2007 Midnight Blue
Sky RL 2008 Carbon Flash - Naked