akira34 is right, but I thought I'd lend my voice to it. In the Pentium 2 era, you could leave cooling up to the CPU HSF that came stock with it, and the PSU fan(s).
No more. Personally, I'd have one intake and one exhaust fan in addition to the CPU fan before you start setting up the BIOS and installing the OS. If you have a midtower case and especially if you don't live in Alaska or Iceland, the interior temperature profile is likely to be warmer.