In all honesty, there really is no best time. Really the best time to buy IMO is when the newest hardware gets released - and that's usually around June / July. It usually starts with CPUs and motherboards, like you're seeing with Haswell this year and Ivy Bridge last year. And then Broadwell next year. Then you start seeing the new GPUs, monitors, cases, peripherals, and everything else trickling out as the year progresses.