Being on a tight budget, and with no preconceptions about needles, I starting building up a pile of what I thought were necessary needles for the projects I wanted to work on. Most were plastic, with some metal (aluminium) as well. When it came time for me to get double pointed needles, I searched around and found some really cheap on ebay. They were bamboo, and I instantly fell in love with them. Now, they are easily my favourite type of material for needles, and I get them wherever possible.
Because my first projects were in the round, I've gotten used to working with shorter needles. I recently picked up a pair of straights, and thought they were far too long. Granted, they were 14" needles, but it's going to take a special project to ever make me work with those again. Sad really, they were my first pair.
I'm making the Concerto on a pair of 10", size 8 (5mm) needles. They are absolutely awful, but 5mm were the best fit for the yarn, and I only had the 10" and the 14" straights in that size. They rattle and don't slide very well, but at least I have the lovely yarn to make up for them.