I'm currently using some Haruhi christmas theme...
Then I usually switch between random Lucky Star, Haruhi, EBA pictures.

(Which are better than most of the themes in the marketplace >_>)

Is there an actual tool to create your own themes or a website..

rather then insert my thumb drive and use a wallpaper as a theme i have live but don't have the money at the moment to get the points you use to buy stuff if theres any for free please let me know i am sick of using my current themes

Right now I'm using the Naruto theme based on the Naruto: Rise Of A Ninja game. It's a pretty nice theme. I just wish you can preview/test the themes before you purchase. I know the XBOX 360 website has some previews, however a lot of the newer content isn't on the website. A lot of times it's hit and miss with a purchase and I'm not one to waste money.

I use custom themes too. I get what I want to see without having to pay that stupid 200-500 points. It usually changes every week like my computer desktop. Right now I have some x-mas anime pic up there, before it was a gurren lagann pic. I probably should change it to something else now that the holidays are over...