I'm going on the assumption that you don't want to pay out your ass for a PC. So here is a few that are decently priced and will still allow you to play games at a great FPS:
snipzipper's Completed Build - Intel Core i5-4460, EVGA GeForce GTX 750 Ti, Raidmax Super Hurricane (Black) - PCPartPicker
philip's Completed Build - Intel Core i5-4570, MSI GeForce GTX 770, NZXT H440 (White/Black) - PCPartPicker
pardonmyownage's Completed Build - AMD A10-7850K, MSI Radeon R7 250, Fractal Design Node 304 (White) - PCPartPicker
For peripherals:
Mouse - you can never go wrong with a Razer Deathadder, Razer Naga, or a Steelseries Sensei.
- Deathadder: Razer DeathAdder Chroma - The World's Best Gaming Mouse
- Naga: Razer Naga Gaming Mouse - Ergonomic MMO Gaming Mouse
- Sensei: SteelSeries - Gaming Mice - SteelSeries Sensei
Keyboard - most mechanical keyboards. It's just what brand is cheaper. Steelseries or Razer are have good keyboards.
- Steelseries keyboards: SteelSeries - Gaming Keyboards
- Razer keyboards: Razer Gaming Keyboards & Keypads: Ergonomic Keyboards, Programmable Keys & More - Razer United States
Headset - I use Razer Kraken Pros. For the most part they are really good for the price. If you want to ham with a headset, Astro A40s are what you'd want. They are $150.00 (without shipping), but that is straight from the Astro site. I'd check Amazon or something for those.
- Astro A40's: ASTRO A40 Headset | ASTRO Gaming
- Razer Kraken Pros: Razer Kraken Pro - Analog Gaming Headset
Hope this at least helps with decisions.