Which is best fluoro bulbs?

I have done some searching on here and on the web elsewhere and have not come up with any real answers. I am looking for some fluoros for my veg cab, and i am so confused with t5, t8, t12 bulbs, which ones are you guys using to veg? I am looking from some around 3 foot that hold a bank of 2 or 4, just not sure what gives you the best bang for the buck! Right now i have 6 23 watt cfl in there and that seems to be good, just trying to get something with a smaller profile and maybe less heat if possible.