If you are going to buy some gaming stuff.
I really recommend not to buy some cheap plastic mouse by Razer. Longtivity is what matters when you are buying a mouse, and a good feel to it, is a bonus.
Gaming wise, a mouse won't really change anything, except having some extra buttons for sprinting, etc.
R.A.T 9/7 (100 Dollars) are great cost a 100 dollars or more, will last a couple years, if you take good care of it.
I currently have a M60 Vengeance Corsair,(60 Dollars) which I love, feels great with two extra buttons for the sprint button in 1.7.
If you are going to buy a 40 dollars mouse by Razer. Steel Series Normal Sized Mouse Pad, with a Laser mouse, (R.A.T 9 and M60) You do not need a mouse pad, but seeing that the Deathadder is optical it does.
Now, let's talk about keyboards.
Now, keyboards really don't matter how you PvP. Of course, if it's extremely changed with some keyboard sins, I don't recommend it.
Now, to make it simple, Razer Blackwidow, why?
Tactile, tactile tactile, cherry switches. Cheap for a gaming keyboard too, but any cheap keyboard from Bestbuy will probably work just fine.
If you just want general computer reviews about stuff, LinusTechtips is a great channel :3
I forgot to add: Mech Keyboards are the keyboards which great tactile/sound with them.
Membrane are the ones with no sound and pretty much horrible feel when you pass them.
Mech Keyboards have a lot more keystrokes, it doesn't get wore down fast, where Membrane do.
Laser mouses will work on any surface, but a mousepad is recommended
Optical only works on certain surfaces, (Mousepad, textbooks, etc)