Must have poker software ????

I play probably 8 hours a day 4 days a week. I dont play 2 many cash games. but when i do i make a small profit playing the small stakes. I play Mtts and sngs majority.

I am wondering from you experienced players is there software such as poker tracker etc. that i should have? I'm not really looking to purchase anything and dont see how PT helps as much with mtts and sngs.
I want some software that maybe has graphs and such. One thing i loved was poker spy calculator, but i tryed getting a illegal key which worked for about 3 days then i cant even attempt to purchase it. Anyone know any calculators that are free that work with Full tilt? or anything else that would be beneficial. Thanks.