There are many of us here who knit with circular needles......and many different likes. The favorites seem to include:
Boye NeedleMaster - a set of interchangeable needles that are metal
Denise Interchangeable - a set of interchangeable needles that are plastic (but knit like bamboo) and have more needle sizes than the Boye's
Addi Turbos - are not sold in sets and are a light weight metal/brass
This thread has LOTS of details about the interchangeable sets. There are quite a few topics out there about Addi Turbos.
The nice thing about the investment of the interchangeable sets is you pretty much have everything you need right away and the extra cables come in handy for many things.
I personally use addi turbos and love them....but I haven't tried either of the interchangeable sets.
I hope this helps!!