Lisa read my post on the Signature dpns and asks about their straight needles.
I have one set - I'm not much of a straight needle knitter myself, I find them too long. It sounds silly, but they get caught in my bracelet.
I do have a single pair of the 7 inch needles in the 4.5mm size - the size I used most often for demonstrations in my classes. I'm teaching a fixing mistakes class this week, for example, and I have a couple of swatches I like to have on needles.
There is a major difference between the straights and the dpns - and that's the bodies of the needles. The straight needles have very slick bodies; the dpns are slightly grooved so that your knitting stays in place.
You can also get different points with the straights - Stiletto, Blunt or Middy. I'm a Stiletto girl all the way, but I can definitely see the value of blunt needles for fuzzy or splitty yarns. You also have a choice of decorative ends, which I think is a lovely touch.
Again, colour coded by size, which is not to be underestimated. (In my Fixing Mistakes class, one of the confessions I hear quite regularly is about knitting with mismatched needles...)
Again, they are an investment, and might not be for everyone - but they are tremendous, tremendous tools.
The yarn, BTW, is the amazingly soft, warm and delicious bamboo blend sock yarn from Bijou Basin. Am noodling on a scarf/lace idea for it and I have been swatching. I do love the Signature needles for lace because the famous Stiletto points are unbelievably good for all that decreasing.
(I'm not being paid to advertise these products, I promise. I'm just a fan!)