Don't get a G15 unless you absolutely want to.
The G15 keyboard only costs $60-80+ online.
http://www.google.com/products?q=G15%20keyboard&oe=utf-8&rls=org.mozilla:en-USfficial&client=firefox-a&um=1&ie=UTF-8&sa=N&hl=en&tab=wf
If I were you, I'd stick with a basic keyboard for typing, and go with a "game pad" instead.
For example, the Ideazon Zboard Fang gamepad.
They also have the gamepad WITH a keyboard attach, lol.
http://www.everythingusb.com/ideazon_fang.html
There are scores of different game pads which, in my opinion, are superior in every way to [gaming] keyboards.
Game pads also tend to be cheaper than the price of a G15 keyboard.
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I have had a G15 for over 4 years and have only ever used the macros in TWO games.
The first being MMO Dark Age of Camelot, where I used it to stick to a target, attack, then do a 0.18 micro move (JUST enough to get to their "side" and followup the attack. Didn't really need it, and it was sometimes annoying/broken bc you cant stop the macro (like if you miss or accidentally press it).
The second being Darkfall, where I found the macro code to spam the G15 macro key while hovering my mouse over a backpack to drag all the loot items into my backpack almost instantly. Loved it here.
So I regret having EVER bought it- since the keys are so out of the way it's VERY annoying. You can't really use anymore than 2 keys while running around with WASD. It's just not worth it. The keyboard itself is also really big.
It is nice to have a stopwatch + countdown timer though on the LED. That is the most useful thing I've had, but certainly not worth the $150 price. The LED backlight is the best part about it, which you can get with a very nice $40 keyboard.
If you want a gaming keyboard, I'd check out RAZER's keyboards instead. I haven't got mine yet, but they boast "anti-ghosting" technology which fixes the problem with keyboards when you try to use more than 2 buttons at once.
In almost every game I play, I try to run forward (W) while at the same time strafing (Q) and turning left (A) but i can't because the keyboard blocks the third button. It is SO annoying. Razer's claim is to fix it. Plus I believe they also have macro keys on it.
I mention the game pad because I can clearly see how much more beneficial it is to use one. There's two problems though, which are the reasons mine sits idle collecting dust.
1) Game pads require getting used to. It's completely different from keyboards. I am too impatient to sit there and learn how to use it when I could just grab my keyboard which I already know how to use very well and play.
2) If you play MMO's where you need to type, it's very annoying to have to grab your keyboard to type, since you can't type with the game pad. If I didn't play MMO's, or if my keyboard was so large (G15) this wouldnt be much of a problem.