Oooh, how fun, you're going to love them!
I bought all of the sizes that didn't come in the set, myself. *blush* For, um, both sets, as I have both Nickel and Harmony sets. I also bought two more of the shorter cables, and one each of the other sizes.
I'm also fine with the bag that they came in -- I cut the size labels off the packaging and stuck them into the little pockets, but think eventually I'll print out some slightly neater size labels on my printer and stick them down with tape, as the cardboard slides out of the pockets sometimes. (We don't get the little tags in the UK kits.)
As for fixed circs, I have most of the smallest sizes in various lengths, mainly in Addi, but they're a lot cheaper here than there. I suppose it'd be smart for me to get every size I want in Addi before I come back to the States!
Have fun with your new tips!