Pimp Your Screen
I LOVE this app for all size iOS devices, but the iPad wallpapers are all so detailed and unique. There are background with shelves to make it look like your apps & app folders are sitting on a shelf (wood, metal, flowers, etc). There are also lock screen backgrounds and icon borders. And an awesome feature that I haven't seen anywhere else is a Lock Screen creator - you pick one of their very well designed backgrounds, then can select your own photos from your photo library or add this month's calendar, or several other unique skins (like tearing paper). The water background with photos of your kids from the beach would make an awesome background! And if too many choices makes you overwhelmed you can browse just the most popular backgrounds.