National Geographic World Atlas
National Geographic provides the best App for political boundary maps on the iPad. Maps from Apple is fine, but sometimes you need know more.
Cymbol
Cymbol alas allows iPad trademarks, sections and superscripts! Finally a way to notate intellectual property or isotopes natively on the iPad while on the go. Plus the ability to do arbitary Unicode conversions opens up everything with context. Numbers now allows me to have footnotes with Cymbol based text options. Pages, well you can have paragraph (they call them Pilcrow) and section markings. Package design options are in there too, Recycle and Kosher symbols, plus others relevant.
Words With Friends HD
Works awesome with multiple concurrent games and players. They had a few bumps in the upgrade, but those seem to be mostly fixed now.
GameGlyph
Have you wanted to e-mail or just use Notes on your iPad to document your winning card hand? Bridge or Poker? Chess game moves, well GameGlyph is the only good tool to create game notes that can be e-mailed to other iPad users, written up in Pages or even put into Keynote presentations to spice those up!
Clapboard
The least expensive good Clapboard software for iPad. Visually correct and suitable for young aspiring film stars to basic video production for putting people on task.
iBooks
Maybe you missed it, but for reference and no charge CIA World Fact Book editions from multiple years are there to complement the data in World Atlas HD from National Geographic. Myriads of books are there pay and free of course.
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iAnnotate PDF
New tool from Aji for me, but finally a way to copy and paste from PDF documents far better than anything else I have found. Highlight, add sticky notes and search just better that the basic tools for iPad.