Never thought I would say this, but as Apple releases newer versions of iOS I am finding less and less reasons to jailbreak my iPhone, with that said...
Currently installed on my iPhone 5:
asktosend - still useful
asktocall - still useful
applocker - still useful
ncsettings - still useful
safari download manager - not that important
winterboard - not that important
iCleaner - still useful
iFile - still useful
3Gunrestrictor - not that important
Peekly - not that important
I really am contemplating removing the jailbreak on my iPhone 5 for the release of iOS 7, as I don''t think I'll miss it as much.
Now regarding my iPad 3, that's a different story as I absolutely can't do without
XBMC, Applocker, iCleaner, Safari Download Manager, ProTube, DisplayOut, iFile and a couple other minor tweaks.
It's strange because when I first bought the iPad, I didn't really see anything worth jailbreaking it for..but gradually over time I've built it up to be an entertainment power house gizmo

I really like the sound of the rumored iPad 5, but unless iOS 7 is jailbroken, it will be hard to part with my JB iPad 3.