There are very few live wallpapers that have ever captured my attention for more than a few minutes. Until Alien Shapes, only one LWP had ever managed to stay on my phone for more than a day or two and that was the Super Mario one.
Alien Shapes is incredible, beautiful, and a rarity for me to say that it's well worth plunking down the $1.99 to purchase the full version.
It's something you'll notice on a person's phone right off. It adds a solidity to your icons as wisps of vapor, textures, shapes, and forms muddle about in the background swirled seemingly at random in a visual cacophony of awesomeness.
The only drawbacks are that you won't be able to stop watching it and that it makes it next to impossible to get good screenshots of your home screen with apps like ShootMe on the EVO 3D, which probably isn't much of an issue for most.
The developer, conscious of how much juice a live wallpaper can drain, has some battery saving functions built in, which are basically to slow the screen updates down. However, remember that your battery is only draining when you're looking at the home screen and the screen is on, which it probably will be significantly more since this thing is enthralling to watch.
The free version comes with 3 skins and 10 color schemes, while the full version ships with 50 skins and 38 color schemes.