It's really a matter of preference; there is no absolute best piece of equipment. It all comes down to what you want to get out of your equipment. I typically go for balance, so the Calibur series suits me well there, but a LOT of people like the Cutter series for the speed, even though the damage output is a joke.
As far as a gun goes, it's more about utility then raw damage. As such, I go with a shock series. There are a lot of good bombs out there though if you like to kite.