My favorite tweaks are Intelliscreen X, Springtomize and DreamBoard...and it is all lost until a jailbreak for iOS 6 on the iPhone 5 is found. In less than 24 hours, @chpwn posted an image of his iPhone 5 with a comforting icon on his springboard...Cydia.
Jailbreaking a personal device is much different then releasing a hack for the average joe to be jailbroken. iOS 6 is jailbroken for the iPhone 4, but that is about it...and it is of course due to the old A4 processor. The original iPad would be jailbroken as well since it has the A4 processor, except that Apple isn't supporting the oldest iPad (March 2010) in iOS 6.