Enhanced Email The Fire's standard e-mail reader does not connect to MS Exchange servers - EE does. And it's a nice alternative for Android phones as well.

CalenGoo The Fire doesn't have a native calendar program, and if you want to check your schedule to see if you have enough time to read that e-book, you'll need Calengoo to connect to your Google Calendars - and it connects to MS Exchange servers for corporate calendars as well.

Wifi Analyzer The Fire is Wifi only - you may need to find the nearest and strongest connection if you need to get online or download more content - Wifi Analyzer will help you do that.

Pulse News For reading RSS feeds on the Fire, Pulse is the way to go. It's not as slick as Flipboard on the iPad, but it gets the job done. You bought the Fire to read content - this is a way to read some of the online content from RSS feeds.

Evernote If I could have only one app it would be Evernote. Evernote doesn't help overcome any weakness in the Kindle, as the four previous suggestions do, but I find Evernote so essential to all my various computing gadgets that I just had to include it.