Have you rescued the kid yet? - if not then you should be able to talk to & get squidhead (Visquis?) to attack you. After that all the guards will attack you on sight.
My favourite combination is green single bladed, and violet short blade in off hand.
I've also just found a new blade colour that wasn't there the first few times I played KOTOR2 - cyan (sorta light blue). Is this because I finally managed to download the second update?