I've been through the store and there themes are less than desirable. I happened to come across a thread on another forum with a great site with loads of themes. I feel in love with this one though. The grass in the backdrop looks almost lifelike.
I took a photo of this. Man my tv looks like the backwoods now! Sorry its a little blurred at the top but I took it on my cell.
You can download it here. Download
Main Site is here
if you want to browse. Fill free to post up any sweet themes you find.
In case your wondering how to install you need a flash drive. Create a PS3 folder then within it create a THEME folder. All caps exactly as I typed. Then go to the theme settings page and at the top you'll see install. Then select your storage device and install it. Then after the install load it up.