Well, I guess I'm in the minority, but all I have are Boye needles and I like them just fine. However, I've never tried anything else.
I had bought Boye needles in most of the sizes that I need, and I haven't bought any new ones in a long time. I do agree that circulars, really a set of interchangeable circulars is the most efficient set to get, since you can use them for anything. My only complaint with circulars is that sometimes when I'm using really big needles, like size 10, the stitches will sort of 'stack up' at the point where the narrow cable tapers up to the wide needle, and I have to stop knitting and fix them.
For very, very small diameter knitting (the tops of hats or socks), you'll either need a long enough cable to do magic loop (I don't have this), or circular needles of the same size, OR a set of double pointed needles.