I guess you haven't modified your "host" file yourself? Have you ever used Tiny Umbrella? It has an option under "Advanced" I believe which sets the host file to Cydia on exiting, or not if you un-tick the box.

If you restore to 5.0.1 you'll want the file to point to Apple's servers since 5.0.1 is still signed and officially supported. If you restore with shsh files to an older firmware (not applicable in the case of an iPhone 4S though) you need to point that file to Saurik's server to make it work (and also use Tiny Umbrella and not just simply iTunes as you can do for 5.0.1 at the moment).

Have you restored before jailbreaking and did it work then?

Did you restore with iTunes before jailbreaking and did it work back then? Is your host file edited and still points to Saurik's server? If so you'll need to point it to Apple's servers since 5.0.1 is still signed and officially supported.

Also I think that using that "erase all content and settings" thing is NOT a good idea because afaik it also makes the firmware unusable (removes ALL content on the device ...), and it's a really bad idea to do that if you have problems restoring in iTunes. ;)

Haha ;p.

Look around (as in, google it ;) ) for other people experiencing unusual amounts of data usage, especially after installing iOS 5(.x.x), I did read about a few people having problems shortly after 5.0 came out, but can't remember what the cause was (if you feel like searching, it was on the macrumors forums). Do you use Siri a lot? I think it definitely uses up some data if queried a lot during the day ... .

True, but it only works (so far) for non-A5 (iPad 2, iPhone 4S) devices.

"But they would rather spend countless hours creating a jb for every single firmware."

You do realize that an unlock without a jailbreak for that firmware version is useless? And that a jailbreak is the prerequisite to even be able to install an unlock? ....

Try respringing manually (with the help of sbsettings or other such tweaks).

There are tons of good applists if you just google or check out modmyi - they recently had two (paid and free) lists which apps to check out if you've recently jailbroken your device. I'm assuming you mean Cydia apps, everything else is not to be discussed here.

Look at the comment on the second page here that starts with "camera roll got wipe after jailbreak, how do you recover?", you can try to respring and / or reboot or re-sync from your iTunes backup.

I don't think that a browser search catches all replies due to the nature of the comment system ;(, I'll see if I can find it again.