Yeah for practice Viper Venom will be what I am using, the price and quality make it the best choice.
My choice for tournaments right now is Anarchy Fury- bright orange- I'm talking NEON orange) or Anarchy Chaos I wanna say (bright yellow) I like Proball Platinum also but its shelf life is a little short and its quality can change if the temparture changes real suddenly(which it does here in NC 30 in the mornings to like 75 on a warm spring day). Anything by Powerball is good but it tends to be a little hard for my tastes.
All RP with the advantage shell is accurate as piss and if you can get JT paint which has the advantage shell then get it. It is so bright.
I haven't shot any of the Diablo paints but I have heard nothing but good things and plan on trying it once our sponsor store starts carrying it.
Your best bet is to try many brands and find one you like.
Good Luck with the search man
Later
Jake