St Petersburg stitch has to be up there as one of my favourite and most used stitches. It makes up a beautiful length on it's own but can be added to easily, increased and even made into a circular piece of beadwork.
Any size seed beads can be used for this stitch, normally 2 colours, one for the main body of the stitch and one for the tips. The tips can be changed up for a number of other beads including but not limited to crystals, glass beads, bugles or even semi precious beads.
I have always stuck to a standard beading thread for this stitch as I like the fact that it creates a very flexible chain. If you are looking for something with a bit more stability you can use fireline and this will create a much stiffer piece of beadwork.