Here is a list of 3rd party iPhone apps that I would recommend everyone to install on their jailbroken iPhones. I have been using them for quite some time and believe that they will make your everyday life much easier. You can install them using the Installer application on your jailbroken iPhone. They are listed according to their categories in the Installer:

1.  System:
   • Installer: You probably have this if you unlocked your iPhone using Ziphone. If not, use iBrickr to install it.You will need this to install the following apps.
   • BSD Subsystem: These are UNIX tools for the iPhone. An absolute must have as this is required by many other apps. This is a pretty big app. Install it over wifi.
   • Open SSH: Install this if you want to access your iPhone using SSH over wifi. You can do a lot of stuff using this as you can login as root. I don’t use it much but its kinda cool to have such an app. It does not add any icon on your screens and can be turned off using Boss Prefs (described below).
   • SummerBoard: Another absolute must have to theme up your iPhone. Another comprehensive alternative is the Customize application. However, I found it overwhelmingly comprehensive. So unless you want to change little details like the battery icon, go with SummerBoard.
2. Sources:
   • Bigboss’s Recommended Sources: Install these to get access to a lot of useful apps from Bigboss.
   • Community Sources: Needed to get access to many of the below mentioned packages.
3. Utilities:
   • BossPrefs: This is a great app to instantly turn on/off many of the settings of your iPhone. I use this a lot to switch on/off wifi, EDGE, Bluetooth & SSH. Saves a lot of taps.
   • Converter: This is a unit converter for the iPhone. Its handy in situations when you have to convert from US$ to INR. Or from miles to kilometers. It also has the capability to download the latest currency conversion rates from the internet. Neat !
   • Taskbar Notifier: This utility adds icons to the status bar (the bar on the top of the screen) when you have unread mail, SMS or missed call(s). This is extremely useful for email as you do not actually get to know that you have a new email unless you are at the home screen.
   • Touchpad Pro: This is a neat utility built using VNC to control your mouse using your iPhone. Well, actually more than the mouse. It lets you use your iPhone as a touch pad. You can move the pointer, click, double click, right click, drag and also type in using the iPhone’s keyboard. Great when watching a movie while lying on the bed.
   • Funiculus: This is a microphone based guitar (and many other instruments) tuner. It graphically tell you if a string is too high or low. You adjust the strings one by one to tune the guitar.
4. Productivity:
   • Contacts | Home Screen: A small utility to put the contacts app to your home screen. Saves a tap to reach the Contacts.1.1.2 and above only.
   • PocketMoney: A comprehensive tool to manage your finances. Use this to keep track of the money you have lend to your friends.
   • MobileToDoList: A small ToDo list manager. Very useful to remember things to do.
5. Network:
   • Bookmarklets: Adds useful bookmarks to Safari. iTransmogrify, Find text etc.
   • smartRSS: An RSS reader for the iPhone. I would recommend using the iPhone optimized Google Reader in Safari as it allows you to read the feeds in landscape mode as well. smartRSS is good for offline reading while in airplane mode.
6. Multimedia:
   • CameraPro: Some professional features for the iPhone. Adds digital zoom. I particularly like the capability to take black & white photos.
   • iFlickr: Take a pic and upload it to your Flickr account instantly !
   • MxTube: A You Tube video downloader and viewer. A little buggy but useful.
   • SendPics: Send photos taken using the iPhone’s camera in full 2 MP resolution.
7. Games:
   • Towers of Hanoi: The great game of the Towers of Hanoi. A must have for geeks. Great time pass. Always challenging.
   • Tris: The classic Tetris game with great visuals and innovative controls.
8. Tweaks:
   • Smb Themes Fix: Yo need to install this only on 1.1.3 or higher iPhones for SummerBoard to work properly.
9. Toys:
   • Flashight: This a small app which shows a blank white screen with maximum brightness. A little heavy on the battery but extremely useful to find something in the dark.
10. Unlocking Tools:
    • ZiPhone iBrickr Fix: iBrickr does not detect ZiPhone unlocked/jailbroken iPhones without this. Install this if you want to use iBrickr to upload ring tones & files to your phone.

Thanks to the people who developed these !

Did I miss anything? Please add it to the comments.