If you need a really good random number generator take a look at Math::Random::MT. It appears to have a very well tested pedigree (within my limited ability to judge such things), it is a drop-in replacement for the standard (pretty good) PRG, and when I first investigated, it easily stood up to some fairly extensive specteral testing I did (Re: Testing for randomness (spectral testing)) a while back (I ran my test in the background continuously for well over a week!).