new computer gtx 980 + 4690k arma 3 ultra

That's a pretty darn good build, I don't play Arma 3 but you should be able to max out most games.

Unless you're doing some extreme over clocking or live in a hot area with no air conditioning (you live in Canada so probably not) then you don't necessarily need liquid cooling. You could go with a Cooler Master 212 EVO for the CPU cooler and use the money for a bigger SSD/second SSD/HDD