Sparrow, one of the best third-party email clients on iOS, doesn't support push notifications. Sparrow+ changes that, while also giving the app an iPad layout and letting you set it as your default email client.
How could we not include SBSettings? This classic jailbreak tweak gives you a quick drop-down menu for a variety of system toggles. You can customize it, theme it, and even view it in Notification Center.
iFile, a full-fledged iOS file manager, sits next to SBSettings in the pantheon of all-time great Cydia apps. It gives you complete control over your device, at root level.
Copy, paste, rename, change permissions ... iFile hits all the marks you'd want a file manager to hit. Unless you're familiar with the iOS file structure, though, we'd recommend using with caution.
If you don't use the iOS Newsstand app, you might want to hide its icon. Unfortunately, Apple doesn't let you put it in your "crap I don't use" folder.
Jailbreakers have an easy solution. Install NoNewsIsGoodNews, and marvel as the Newsstand icon evaporates. If you have any Newsstand magazines, their icons will move to the homescreen.