Personally I'm a PC gamer and have always viewed consoles as limited, but that's just my opinion.
With the addition of a discrete GPU and some controllers your current base set up is adequate to game on at a level that should surpass the xBox One and PS4 for under a $350 spend.
Your PSU probably just scrapes in. Most GPU manufacturers recommend a minimum 450W PSU, however this is based on worst case scenario (ie cheap poor quality PSU which is likely to fail at high loads which is full of dust). Your Antec 400C PSU is of reasonable quality and the load on your system should never reach this (I've overclocked my gaming PC and struggle to get to 350W under full load).
A big beefy CPU isn't essential, as with most modern games the GPU is typically the bottleneck, particularly for running titles at 1080p60. Modern GPUs have come a long way in terms of noise, heat and power consumption. Fan profiles can generally be tweaked with the supplied software to satisfy acoustic requirements (ie maintain near silence when idling/performing HTPC duties, and an slight increase in noise when gaming). There is an increased power consumption for idling, but it isn't huge. Most hardcore gamers are enthusiasts and will always strive for extra performance (even if it isn't appreciable other than in FPS or benchmark scores), continually spending money on hardware. For everyone else, a lower spec'd system will still give a satisfying experience.
The following GPUs would meet your requirements:
- nVidia GTX760 - Gigabyte, Asus, EVGA and MSI all have cards around the $250 mark with very efficient and quiet coolers.
- AMD Radeon HD7950 - Gigabyte, Asus, Saphire and MSI all have cards around the $245 mark with very efficient and quiet coolers
For controllers I use a pair of Logitech F710 Wireless Gamepads (around $45 each). They perform pretty well, although I do find I get some issues is the wireless dongles are located too close to each other on the PC. They do come with a USB extension cord for the dongles which fixes this problem. Have had them for 6 months with light gaming and so far haven't had to change the batteries.