Yes Evernote is an amazing app. I look for apps that will sync between all of my devices as opposed to something that will be on my phone only. That way if theres some issue all of my data is still in the "cloud" and available.

I haven't used K-9 but I might give it a shot. I use the standard mail client for my exchange and the Gmail client.

Barcode scanners are awesome! I use Red Laser and Google Shopper. I like being able to scan a product and compare the pricing to whats available at the store.

Pandora is ok but for music I use Subsonic. It turns your pc into its own server and creates your own "cloud" to stream music from. It has a web interface and apps for Android and IOS. This works out great for me because I have a large music library and I can have it with me at all time.

Astro is a must have.

I use Barnacle for my wifi hotspot.

Sky map is one of those apps that I had to drag the wife out late at night to show it off.