i didn't bother to read EVERY thread on here, but a thing to beware of with linux USB / live CDs: if your encryption requires high-quality random numbers, you might not want to generate random keys after booting from a USB boot / live CD; apparently that's not a good choice because the environment is more predictable. Anyone out there ever even take advantage of this flaw? I sure haven't; I've only had wikipedia entertain me with these thoughts
Honestly, it surely doesn't matter, but for those that love being paranoid: beware of generating keys after freshly booting from a live CD / USB.
As for creating a "100% secure wallet", I don't think it's possible to quantify or measure the % of security that a wallet is under. Keep in mind that your wallet isn't exactly secure if even YOU lose access to it! (It's no longer secure--it is useless!)
im totally lost
Computers don't actually generate random numbers - they don't have the hardware for that. Instead, they use a function that has been shown to produce an evenly distributed, unpredictable result, as long as you don't know the number they start with, also known as the 'seed' - many generators use various information from your computer's memory as the seed. Since a Live CD / USB tends to boot up nearly the same each time (since you don't have a lot of user installed programs starting up every time you do), the actual variation of the seed is lowered, meaning that someone with a sufficiently complicated algorithm and some knowledge has a higher chance of generating the same keys.
Just do some stuff to change the state of your memory before you start generating keys - play some solitaire, pop open a text editor and mash on your keyboard for a while, save that file somewhere... whatever. Of course, you only need to generate keys occasionally, so you mainly want to be careful when generating your original wallet file.