Photogene for iPad Chosen because it can do so many things. It's also one of the few iPad apps that can paste pictures from the clipboard into the photo library--this feature alone is priceless!

SketchBook Pro Allows me to mark up image files with handwritten notes, doodles, and comments--key for working with designers around the globe.

Evernote Evernote's multi-platform availability makes it great for always being able to access the same data regardless of whether you are on a Mac, PC, iPhone, or the iPad. I use it to manage frequent flyer membership numbers, cultural and business etiquette data on various countries, and for collecting articles to read when in transit.

Simplenote I use this as a more instantly accessible version of Evernote for my daily "to-do" list and other fluid daily uses.

StockWatch - iPad Edition Great iPad interface plus you can use their sync service to keep the data the same on all of your devices.