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I use these daily:
NetNewsWire
Things
Facebook
Twitterific (I'm just a reader and find it easier on the eyes. I don't care to reply.)

I use all of these regularly:
Mantis Bible Study
The Weather Channel
SmugShot
Remote
Units
Shazam
DirecTV
Tip
Amazon.com

*Note I didn't include any games or apps that come stock.
 
from non native apps

Used Every day:


Facebook
Fring
Boxee Remote
Tweetie


Used Regularly:

Byki French
Qik
gb4iphone
Movies
solitaire city
 
SyncinAblink
Freememory
UKNumbers
Skype
Shazam
IWol - I like to wake up my PC so its ready once I get near it.
Various Japanese Apps, cos Im learning the lanaguage.
 
Sudoku (first by EA, then I got tired of waiting the intro out so I got the Sudoku Unlimited)
BeeJive/IM+ (since I'm on 3.0, they both have their equal share of crashes...but on 2.2.1, BeeJive because of the message history emailing capability)
Facebook
eBay
Amazon.com
 
The apps that have permanent residence on my home screen/s are:

TwitterFon.
Facebook.
Shazam.
Picture Safe.
Free Memory.
Allowance. (For O2-UK customers)
MMS. (For O2-UK customers - soon to be dispensed with, once 3.0 arrives)

The games that have permanent residence on my home screen/s are:

Virtual Pool. (Celeris)
Tetris. (EA)
Wolfenstein 3D Classic. (i.d)
2XL Supercross. (2XL)
Arcade Hoops. (Skyworks)
Flight Control. (Firemint)
 
Take a Note
Now Playing
Facebook
Public Radio
MLB At Bat
Trism
AccuFuel
Grocery IQ
Shazam
WiFiTrack

I have a bunch more that I like, but those are the ones I use constantly.
 
Useful (Productive)
1. iDial - Contact Search (99 cents)
2. Arachnid Lite (free Full Browser)
3. Faces Visual Dialer Lite (Free)

iPhone keypad dialing is terrible for making calls while dialing. iDial and Faces Lite help me a lot. Arachnid full browser doesn't want me to go back to Safari. I might soon buy their full version which is $1.99.

Other well used apps:
1. NBA Game Time
2. Free RSS Reader
3. Movies
4. TVU Player (Let's me watch several Indian Language channels including Telugu)
 
Yeah, it's getting harder daily for each of us to weed through the onslaught of apps to find the one's will make our lives easier. Here are the apps that are USEFUL to me. I have downloaded and deleted many many apps since last summer, and right now, these are the survivors...

Used Daily

- iStockManager
- AppSniper
- BillMinder
- Sportacular

Used Regularly

- American Heritage Dictionary
- Roget's II Thesaurus
- MyWeather Mobile
- Converted
- Take a Note

Used Occasionally

- Briefcase
- White Pages
- Hot Popcorn
- Public Radio
- G-Map US East
 
The apps I use the most aside from the ones that came with the phone (not including games)

Facebook
Tweetie
Myspace
Lose It
Pandora
Shazam
iP (for us ladies)
Mobile News
 
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