*** General Thoughts ***
1) Must lend itself to use in websites (big and beautiful), mobile apps/site (legible even when scaled down), and as a social network avatar (Facebook, Twitter, etc)
2) I'm a big fan of a style I'm calling "modernized retro". Most of my examples below are in this style. I think this concept lends itself well to the brand name, because it's as if modern smartphones are dragging old businesses into the 21st century (ex: magazines/newspapers distributing on the iPad).
3) Colors: needs to be able to stand out on any background
4) Font - not picky, when I design something I tend to use fonts without serifs, and either all capitals or all lowercase letters.
5) No tag line
*** Examples ***
***UPDATE (2010-05-06): The examples below don't necessarily have a *logo* I like, but the show/movie/video game itself has a *style* that I like. If you're familiar with those shows/movies/video games, great, otherwise, you might want to look at the file I've attached to this brief, which has specific logo styles I like.
I like the logo and the style used in the game Bioshock. There's a kind of "modernized Art Deco" feel going on throughout -
The movie The Incredibles, the video game Team Fortress 2, and the TV shows Archer and The Venture Brothers use a similar "modernized retro" style, which I'm a fan of: