I'm launching a new gaming channel called "King Kousky", so my logo will basically only be virtual based (i.e. not printed). It will be set as the avatar (profile picture) of my YouTube page, so it will mostly be displayed small on screen (about 1in by 1in). Therefore, it's more important that the logo look good when displayed small rather than large. This means that a long, rectangular logo wouldn't be ideal, as the YouTube profile picture is a square, so the long rectangular logo would have to shrunk even smaller to fit the dimensions of a square, and it wouldn't fill the space well.
As for the content in the logo, I'm open for pretty much anything. It could be the initials "KK", similar to the example logos I included for a channel called "Captain Sparklez" (note the two logos with "CS" embedded in them). Or, it could include the entire name "King Kousky", but only if you can make it in a way that looks clear when displayed small. And, if you have an idea that doesn't incorporate "KK" or "King Kousky" feel free to submit it and it could work. For an example, you'll see that I included two example logos for a gaming channel called "Node"; one includes their entire name, whereas the other includes just the first letter, "N". How you make the logo is up to you, so I encourage you to try everything in your imagination. One example would be to somehow incorporate a crown into the logo. Also, experiment with simple ideas, as well as ideas with more features such as shadow, gradients, bevel & emboss, borders, etc.
Because I'll be doing minecraft videos, most of my audience will be young (8-14). However, I still plan on working with more violent games, such as Battlefield 4 and Call of Duty, which entails that part of my audience will be slightly older. So basically, I don't want my logo to look like its for little kids, but then again, I don't want it to be completely serious- it should still have childish aspects. You'll notice in the example logos I provided, two of them are for "Captain Sparklez" which is a younger target demographic, whereas "Node" is for older viewers, and looks more mature.
In designing the logo, keep in mind that it will be used to create a 3D animated video intro. It should also be flexible with changing its color or texture, as you see with the CaptainSparklez example logo, one is red and yellow, while the other is a fire texture. Bonus if you submit the logo in a variety of colors/textures.
Any questions please ask. I hope my guidelines aren't too specific, as I really want this to be pretty open ended so you can use your imagination as much as possible.