Emelth :
I would go with the Logitech G510 Keyboard and Razer Naga mouse if your playing MMOs
I second this combo, playing in MMOs is amazing with this combo.
PROS: The screen on the G510 works with tons of games, and has a lot of useful information like who's currently talking in vent or TS3. The programable keys are awesome if you are a macro fiend, and it really helps to have them. I use them a lot for raid leading macros and have separate keys for each raid marker icon. The mouse is awesome especially from a healing standpoint where you're moving really fast between healing targets while using the mouse to move. Really helps to eek out that next level in the gaming, for PVP content this is almost a must have, allows you to keep the mouse and have enough binding keys available to keep the keyboard available for strafing, etc.
CONS: The cost on this setup may be prohibitive, and it really takes a lot of adjustment to the new style of gaming.
To answer some of the other complaints: The "fancy screen" really comes in handy if you use it, it's a life-changer and one that you really don't think you'd use until you have it and then don't have it. "How did I play without it?" As to the 5-key isolation, I can see this becoming an issue in games with a lot more presses per second, but I have never personally ran into it playing Diablo, Skyrim, or various MMOs. You're mileage may vary if you play other games. The cords on my keyboard and mouse are more than adequate for me, and my tower is fairly removed from my seat/desk.
BUT: The TLDR version of this post is simple: go to a store that has them on display and try out the "feel" of the device, see how the weight of the mouse and the keys feel to press, then make your purchase where the price is the best.
Good Luck