As far a the white gel pen for writing on dark paper, the Signo Uniball it by far the best pen out there..they sell it here in the superstore.
I've never found a good white ink...I've had better success with white embossing powder, at least it shows up really well, plus it adds texture.
I agree with adding your ink to the stamp and not the stamp to the ink. It really does help.
And the Stickles Black Diamond glitter glue is the best....I use so much of it, I keep a minimum of 4 bottles on hand.