The only two things i think ppl would jailbreak for at this point is to winterboard their phone to make it look a little less like ios 7 does now. And quick reply, like bitesms.
There are still a lot of extra functionality you can get from jailbreak tweaks. Subtle but all add up to be a big improvement to the user experience. May not be for everyone though but I look at jailbreak for functionality > appearance; I don't theme my phone because I don't see the point in it
I notice f.lux is one of the more popular ones out there.
SBSettings (yes, there is control center but I don't think we'll ever get the power to customize the toggles we want in control center)
Activator
Display Recorder
FakeClockUp (to speed up animations on a fast device that can actually load up the app quick enough to make a difference)
Widgets to make contacts a click of an icon to call (SBPhotoDial, Lockinfo 5 contacts widget)
iFile
Insomnia (allows for wifi to be on even when in sleep mode; helpful if downloading a large file on device and not actively using it)
Tweak(s) to require password to open an app
KillBackground (kill all apps running in the background with one press of a button)
PasswordPilot (never need to type in your apple id password again!)
PullToDismiss (hide the keyboard in cases you can't; ReturnDismiss: hold the return button to hide keyboard)
QuickStore (doesn't close the app you're in because of some ad that forces the App Store to open to an app)
TapDeWiggle (exit icon edit mode by tapping on the screen; helpful if your home button is dead or if you're using it in combination with zephyr to remove home button reliance)
Webscrollian
3G Unrestrictor (for those on unlimited data plans)