Just starting Mass Effect. Given how much I've read about 'John Shepard', I'm wondering if it is worth creating a custom character (which I would normally do), or if it is best to go with the standard male character?
Shepard is your character's name, if you don't really care about how he looks, then you don't really have to customize him at all.
Most of the story and interactions have little to do with your character origin. There are a few lines here and there that refer to your past, but nothing game changing in the grand scheme of the plot.
What does change the story are driven by the choices you make throughout the game.