CPU: For what you're doing now you shouldn't have to overclock. It's just something nice to have a bit farther down the line when you're trying to squeeze as much life out of it as possible. I would say it's worth getting one even if you don't really plan on using it as it's an option open too you. So, I would hold off on overclocking for now until you need that extra performance. PSU: As other posters have said NEVER SKIMP HERE. See the above poster for what the ratings mean. Adding up the TDP of the CPU and GPU then adding about 10ish for the other components and then about 50 for overhead is one way. Another is going off of what the site DuoDex gave you says. I'd say, with out knowing the parts, about 600-700W. Another thing when you look at the website for the GPU don't go off of the wattage requirement they give you. That estimate is given for the very bottom of the rung PSU that can't deliver there rated wattage. For example if it says 500W then a good quality PSU might only need to be 450W. Also, you actually read the OP!