For headsets and microphone combos, get something that is very lightweight and comfortable. Some headsets are great for music, and make the game sounds come alive, but after 2-3 hours of beautiful sounds, your neck starts to hurt. Music headphones are heavier, because they are designed to be worn while sitting in a chair relaxing. During gaming, you are constantly moving your head slightly, and heavy headphones will start to make your neck sore. The best design of headphones for gaming have a mic built onto the headset, for easy communication. The cheaper headsets are usually lighter, so they work better for daily gaming. The headphones with padded ear cups that surround your ear can start to pinch at your ears after a while, so my favorites are the ones with the basic foam, either behind the ear or over the head. During matches switch to the higher quality headphones for an edge. Use the higher quality headphones enough to get used to them during casual play, and it will make a slight difference in a match. If you never use the high quality headpohones, it will surprise you how much more you hear, and be a distraction during a match.Here is a good headset for everyday gaming, not too heavy, built in mic, and good sound quality.
Plantronics .Audio 60 Computer Headset
The best mouse is the Microsoft (R) optical series. the Intelli Mouse 5 button mouse has always been a reliable favorite. The wireless optical ones are nice, but having a battery go dead during the middle of a match can be frustrating.
This is the best mouse that you can get for the money.