If you want to make some portal-like music, I made a recent discovery that Mike Morasky (composer of Portal 2, Left 4 Dead series, etc) used a VST Plugin called chipsounds. I thought it might be useful for anybody wanting to make some music more close to Portal 2 style than normal electronic music.

Source: http://www.plogue.com/mike-morasky/

Download (costs $100+): http://www.plogue.com/products/chipsounds/

Thanks for sharing!