Saimbor Deng Mukhim

Room temps are irrelevant until you have to deal with 35C+ and high humidity. Then AIOs start to make more sense than just air. But low room temps, the temp itself isn't important when choosing cooler. What features are you looking for? Performance? Price? Looks?

Have you tried using the stock cooler?

I have a 1400 which is very similar to the 2600, it’s from a prebuilt and the stock cooler was really crappy so I got a MA610P air cooler from cooler master and it has Been a great cooler for about a year keeps my R5 at 45-50C even while playing demanding titles like forza. I’d say go with the air cooler but if you are thinking of upgrading to a R7 get the liquid cooler if not then it’ll be very overkill.

depends on the cost of both. a good air cooler and a good aio are temperaturewise not that different in a well ventilated case

You only need air with ambient that low most likely.
 
You're also not telling us WHAT you're cooling, which is important.  

It depends on a lot of things. Are you planning to do heavy overclocking? Do you want a silent build? Stuff like that.