This list says 2s can be 2.75 or 3. very weird.
I personally like the bamboo needles better because they don't get all bendy like the really skinny metal ones do, and it feels like the yarn travels better. With metal, it seems like they're *too* slide-y. Stitches would fall off the end when I'd put things away for the night.
Oh, and I've got a good website for Kitchener stitch, when it's time for finishing the toes. Best visuals I've seen.