95% of my knitting is done on circular knitting needles, straight ones hurt my shoulders and DPN's hurt my brain! So if I got a set of interchangeables it would do for pretty much all my knitting except for small circumference stuff like socks for which I use Hiya Hiya needles:
I've always preferred to spend my spare money on yarn instead of needles. Right up until a couple of weeks ago I got out fixed circular I hadn't knit with for ages and I couldn't get the cable to unkink. It was locked into a tight spiral that got in the way every time I tried to knit and I got fed up.
I'd heard people on Ravelry raving about ChiaoGoo Twist interchangeables and I am so glad I bought some.
The cables don't kink as they have no memory. The tips are pointy without me needing a blood transfusion every time I use them. The needles and joins are smooth, these have actually made my knitting speed increase. I'm in love...
Best of all they come in the prettiest little case: