I have already answered wisdom toilet, but I can see that no one else would choose it. Here is my reasoning:
1. Iron man suit: Can use Wisdom Toilet to figure out how to make.
2. Ring: Who cares? You don't need magic if you have science.
3. Monocle: You can reflect on everything you saw and take in the tiniest details on the toilet.
4. Mech: See Iron Man suit.
5. Keyboard: You could easily figure out how to program anything with the Wisdom Toilet
6. Reincarnation Pill: I'd hate to live forever, and see everyone I know and love die, and watch it happen over and over again.
7. Gabe Newell: No, just no.
8: Zelda: You can use the wisdom toilet to figure out how to get any girl to fall in love with you, no problem.
9: Rei and Asuka: See Zelda.
Therefore, the Wisdom Toilet is clearly the best choice, you can have all the good options because of it.