Generally, I have a very hard time deciding 'what' to
play, and brainstor, several ideas.

I will roll up a small handfull of various characters
class/race combos, and pretty much rank to PK.

In the meantime, I kinda just play around with each to see
which persona better grabs me, and I find more comfortable/curious.

Then once I decide what I stick with, I delete off the rest because
I feel having/playing multiple characters can be detrimental of
the focus you keep on your main character you play, and can cause
some intresting/confusing/borderline cheating situations keeping
character knowledge seperate.

I would suggest to just try a few, but plan to pick and stick
with one, while also deleting any in-active characters to help you
keep more creativity focused on your character, and also just saving
space in general.