I doubt the gloves will make much of a difference for wrist numbness. I found a vast improvement when I switched to ergonomic grips - if for no other reason than the fact that they can be positioned to keep your wrist and arm in a straight line. Lots of people here recommend Ergon grips. I found them to be somewhat large. I prefer the Specialized BG Contour grips, but it's really a matter of personal preference.

As far as tires are concerned, I also run 38s. My personal opinion is that the advantages of going to a more narrow tire are greatly eclipsed by the potential problems with smaller tires. Smaller tires are great for racers, but you won't notice much of a difference at all. If that's the case, then why install something that is more prone to flats and can't go as many places?

You can also run wider tires at lower pressure, which will help with your wrist numbness.