If you are serious about generating random numbers then the best aproach remembering that it is impossible to generate truley random numbers from ANY deterministic machine,is to try to make the number sequence look as far as possible like a white(or coloured) noise source,there are lots of very mathematical tests which will tell you just how much like a true noise source your rng is but they are hard work to perform and they are not totally acurate.So you need to find some metric which tells you how much entropy you need in your noise source and take it from ther,its not something you can judge by eye.
For example,for a cryptographic engine I have seem a reverse biased diode providing the salt for a 128 bit LFSR which is then fed into MD5 which is then put through 9 seperate statistical tests simply to produce some random numbers and if you print them out you can still see what look like patterns in the data.