New computer build time? Or hold off?

[Taem]

Do I want/need an aftermarket CPU cooler? I do not plan on overclocking, but I do value a fairly quiet machine. I don't need total silence either though. I'm not sure how quiet the stock Intel i5 cooler is. I don't mind if it's a dull roar while I'm gaming, but when my machine is idle I'd like it to be very quiet.

I'd vote yes for the aftermarket cooler. I personally go for an aftermarket air cooler (edited for clarity, air vs liquid cooler) but that's me having lower risk tolerance regarding absolute worst case scenarios.

Both types are generally pretty quiet nowadays*, since we're talking about a gaming and more general machine. I prefer air cooler system since it's still pretty good from a price\performance. But both types are usually pretty good nowadays, it's still better than the stock option for the most part, even if you're not overclocking.

*On my main, i7 photoshop machine, I have an aftermarket air cooler installed. It's a fairly large sized thing installed in a full size tower case. But it's a fairly quiet machine to date, opening the CD\DVD tray is louder than the general hum of the machine.

Just a word of caution I'd like to comment on: unless you have proper fan placement for directional airflow in your chassis, you could actually retain heat and fry your system much quicker, especially when you start tossing in energy intensive video cards. Since this is clearly a byo system, just be sure you're familiar with the airflow dynamics of your tower. When I got my new full-sized tower, my computer was consistently running hot which it shouldn't have, so after a little research, I found out that all towers are not created equal, and I had to go online to see what the proper airflow was and lo and behold, I needed two additional fans and had to reverse the direction of another two for my tower. I'm not saying you'll have that problem, but just a word of advise.