One of the things people tend to ignore, is to close the PDF hole that allows you to jailbreak your iPAD. This very "Hole" can allow some malicious Software to cause harm to your iPAD. Closing it wouldn't hart the jailbreak itself, and you can keep using Cydia as usual.
And...how would I go about fixing this "PDF hole" ? I searched around the site but couldn't find anything on it, and on Cydia, the "PDF Patch" was only compatible with 3.x.x and 4.0, I've got 4.3.5
Take a look at that Video of "PDF Patcher 2"
[ame=http://www.youtube.com/watch?v=811kftsKXNo]‪'PDF Patcher 2' Secures Your iPhone From Latest PDF Exploit‬‏ - YouTube[/ame]