A colleague of mine recently jailbroke his iPhone because he could and didn't know how to put it to use. Cydia's discovery mechanism isn't that great so I made him a list of tweaks I had on my device ( using another app, AppInfo ). I am sharing the same here.

UI/UX
 
  1. ActiveDock : Mac like dock with active app indicators 
  2. AndroidLock XT : Pattern Unlock on Lockscreen 
  3. *appslide : Intuitive interface : Mix of Android,iOS and Windows back button flows. App 1 link opens App 2. After consuming content in App 2, returning to App 1 involves pressing Home Button. No more need for App switcher. 
  4. *Auxo : Enhanced recent apps drawer and quick settings access. 
  5. BytaFont : Change system fonts 
  6. Default HD SBSettings : Neat theme for SBSettings
  7. Flowtation : UI animation for Notification Center
  8. *LockInfo 5 : Access email, twitter, feeds, calendar, weather and handle notifications from Lockscreen. The only reason I Jailbreak my device.
  9. SBRotator 5 : Use Springboard and all applications in landscape mode
  10. ScrollingBoard : Scrollable dock 
  11. *Zephyr : Intuitive OS X like app switcher. Each app is treated as a full screen app and swiping from edge of screen takes you to the next app. 
 
Utilities
  1. 3G Unrestrictor 5 : Removes download limits on app on mobile networks 
  2. Activator : Assign actions & gestures to functions 
  3. AdBlocker : Blocks ads 
  4. Browser Changer : Change default browser ( to Chrome for me ) 
  5. iFile : File system browser
  6. MapsOpener : Change default maps ( to Google Maps )
  7. PushTone : Custom sound notifications for all apps 
  8. SBSettings : Settings drawer from Status bar
  9. UnlimTones : Download or create your own ringtones from iTunes library on device 
  10. WinterBoard : Default Themer. Themes downloaded from Cydia will need to be made active here
  11. Xcon : Fakes jailbreak status to apps that detect jailbreak before running