Yes I think we need a big thread to share apps that work with the Kindle Fire and help some of us who are lost at what to use.

Wi-Fi Status Bar Switch by friedflow - Toggle WiFi on/off by touching app icon or in the Notifications bar so you can toggle from any app.

Lock Screen App by Kenneth Cheng (i-Kenneth.com)
Lock your Fire with the touch of a icon. also available in Amazon's app store for $1.99. Market has paid and free version. I use the free one do to placement of Lock button being hard to get to when it's sitting in my stand.

Screen Dim by Omega Centauri Software - Better then screen filter and works great! If you do alot of night reading then you need this app to make the screen dimmer so you don't burn your eyeballs. Also available at the official Market and can be sideloaded.

Mantano - A rich feature epub eReader app. There is free version and a paid one. The difference is one has ads and the other doesn't. Mantano has many options to customize your reader experience. It also has collections to keep your books nice and organize. It's well worth the price.

GSam Battery Monitor - This is the Kindle Fire edition and made strictly for the Fire. The other version is free but it's not as accurate. This app will put the battery percentage in the notification area. It has many more features like predicting how much battery is left. Now has low battery alarm! You can set it to the percentage to notify you when the battery is low. Mine is set to 35%

Aldiko - Another epub eReader that many use. One unique feature this has that Mantano doesn't is that you can download overdrive library books directly into the app.

Overdrive Media Console - This app lets you download library ebooks and library MP3 audiobooks directly from your library's overdrive site. The Fire will not play wma audiobooks.

Please see this thread for alternative markets to find your apps.

If you know of a compatible tested Amazon app store apps please list them as it will help those who don't have access to the Market. Other non app store apps welcome too.

Please do not add links to blogs with lists of apps. I made this thread to find apps that you have personal experience with and can't do without.
Isn't the wifi on/off already in the notifications bar?

Also the lock screen? Pressing the power button is the same isn't it?
No it's the settings bar where that is though you can still access it from any app but it takes a few extra steps with the app I use it just simple click on, click off. It's faster too in connecting/disconnecting.

Yes the lock app and power button are the same. The power button is on the bottom but I don't want to have to pick up the Fire each time to lock the screen. I'm not holding it my hand it's in a stand right next to me like my new best friend and it doubles as a mirror!
YouTube 2.3.4: I used your trick and moved it from my phone to the Fire after creating an APK via ES File explorer.

Also available at: http://www.freewarelovers.com/android/app/youtube


ColorDict: Same as above. BTW: ColorDict works with several of the 3rd party reader apps like Mantano, so it is a very useful app. It works standalone too.

EDIT: In order to get the WordNet 3.0 dictionary data to work with ColorDict, I copied the dictdata/dict folder from my phone to my Fire. It works!
Oh I forgot about youtube! Where do you find it other then Market. My phone comes with a different version so I can't sideload it that ways.
Ok I think I got ya. i'll have to try it out
I read a thread where SCION found it, but cannot remember where she got it, or which thread. Thread had to do with sideloading. I lucked out and my phone app worked. It looks awesome!

Here is SCION's link: http://www.freewarelovers.com/android/app/youtube
PerfectViewer (1.0.7.2) comic/manga reader for android.
Youtube was on my Fire when I received it.

The best App I just got from the Amazon store was the Tecarta Bible. Its the best I've seen. The KJV is free and the NIV Study Bible is only $ 20. After one registers, once can stream dozens of other Bibles FREE via the WiFi.

I spent most of today playing with that App on my Fire.
In two clicks (I have them in favorites beside each other) I can turn WiFi off and lock my Fire which will save my battery.