Best: Love my magnetic pinholder. I can just toss the pins in its direction when I'm sewing and they all end up in the right place!
The table needle threader is funny: when I first got one, it didn't work at all. I put it into the drawer with all of the other useless items, but got it out again when I started English paper piecing (a lot of hand needle threading) and it worked like a charm! I bought another so that I could take it places with me.
Worst: I agree about the Clover mini-iron. I thought it was such a good idea, but find it worthless. Also - I can't seem to get the knack of using the needle threader on my Janome...I think we've had a discussion on this topic in the past!