Imeem Mobile: First in line is the Imeem Mobile - terrific for all you music lovers out there. The Imeem will place or stream music using your phones SD card. There are various ways to listen to the media once you have created an account - which is also free by the way. You can either upload tracks from your hard drive, you can create radio stations using the same smart data that last.fm uses to "customize" your music tastes, or you can listen to pre-set stations that have been integrated by Imeem Employees. One of the coolest things about this app, is that the music or media will continuously play, even when you have other apps going on at the same time.
Picsay: Second, we have the Picsay. This unique little app lets you edit photos right from your phone. This is a substantial app considering a lot of the time you cannot edit anything let alone modify photos using cell phones. You can also add balloon chat, text and various styles and colors as well as various shapes to the photos. Once your photo is done you can send it via email, SMS, MMS, upload it to Google's Picasa, set it as your cell phone background, or you can upload it to your blog or social network!
Shop Savvy: Third on the list is the Shop Savvy. This is a Japanese app that can help you in finding the best deals online! All you have to do is enter the name or scan the bar code of the item, let Shop Savvy search its indexes for the product, and it will tell you the best place(s) to buy the item for the best price (including shipping and handling fees). It's almost like having your own personal shopper right on your cell phone. This is going to be a hugely used app considering over 96% of people in the US have either shopped online or do so regularly.
Twidroid: Fourth on the list is the Twidroid. Everyone knows that Facebook and Twitter have surpassed Myspace as of late, and with this app you can do an array of activities right from your phone. This app allows you to send tweets, read tweets, send replies, DMs, follow and unfollow individuals, etc. You can also capture GPS info and send it into your tweet, geotag photos, plus it offers the usual URL shortening and picture hosting options as well.
Advanced Task Killer:Fifth is the Advanced Task Killer Free. Most of the apps on the droids are really interesting, and you might find that you have a few dozen open at once. This ends up sucking up a lot of your CPU memory (just like on a computer) and can make you lag! That's why an app like the Advanced Task Killer Free 1.5.1 is so important. This will allow you to "auto kill" any app you have running. You can also upgrade for $5 to get extra features, but most people say the free one is just as good!

Astrid: Seventh in line is the Astrid. This is without a doubt one of my favorites. Why? Well, I'm big on organization and to-do tasks. I look and use my Google Desktop gadget "to do" list several times a day. But, when I'm away from my computer, this Astrid 2.10.0 app is the best thing since white bread. You can start put with simple to do tasks, but you can also tag tasks, set various priorities depending on the task, assign dates and a whole array of reminders. You can also set a timer which tells you how long it took you to complete each task!
Google Sky Map: Eighth is the Google Sky Map - pretty self-explanatory. Have you ever seen a star at night or a set of stars and wondered what constellation it was? This map will help you name all kinds of stars, planets and constellations above you. Pretty neat! All you have to do is use your phone GPS locate to point where your location is and it will give you a map of the exact location where you are. Then, point your phone up at the sky and it will display the name and location of the brightest stars in the sky. Definitely fun, but also very educational as well!
Check out the below video to know more about Google Sky Map.Google Voice: Ninth on the list is the Google Voice. I have this on my computer and it is super nifty. On top of being able to listen to voice mails from your computer and receive text messages through your computer, you can also be "beeped" if you set up Google Voice using your cell phone number. You can also have your incoming calls transferred from your google voice to your phone. If you choose to not pick the call up, it will be set to your google voice or cell phone voice mail depending on how you set it up. You can also make international calls from Google voice for Android at competitive rates.

There are several other useful applications like Pandora Radio, Photoshop mobile, Ringdroid, TuneWiki etc for Android powered phones.
To download any of the above application just go to the Android marketplace and search for the respective application.