You should focus more on getting a good mouse, mainly an optic one without any forced-acceleration or so, that will have more impact on your 'skillz' then a keyboard.
I use a Steelseries Rival and I'm VERY happy with it.
First of all, it is a matter of personal taste when it comes to keyboards.
We can assume that the worlds best player in some random game is going to have the best keyboard suited for gaming or for that specific game/genre, but in the end you might not like that type of switch/feel/size/setup.
From my personal experience and what everyone else is saying is that Cherry MX Red and MX Browns are the most commonly used for gaming with MX Red being somewhat in the lead even if MX Brown is more common these days.
Quality and brand does matter, for example the Ducky Shine 3 is more 'robust' then a CM Quickfire board. Stay away from Razer IMO.
LEDs is a personal thing. I find them distracting and also I'm afraid of LEDs dying after some time, can't be arsed to repair them myself or having to go through some warranty support.
Keysets and profiles is also a personal thing. Cherry and OEM profiles are the most common ones.
I use MX Brown and play A LOT of competitive games, mainly UT4. I think that MX Red feels to 'light' for me and I like the subtle bump in MX Browns.
I always use TKL sized keyboards because I never used numpads and it's a lot more ergonomic and faster to move your hand between the keyboard and mouse.
I recommend getting a Ducky keyboard with MX Red or MX Brown! Any model will do, Shine 3 is my favourite, size is up to you.
