Don’t be afraid to experiment with lights. Any bunch on a string will do. I recently made a sparkleball with LED icicle lights I’d found cheap after the holidays, and they worked really well. They seemed easier to insert than the usual mini’s, and their color is pretty. Carl uses old-school C9 bulbs in his retro ball. One of my all-time favorites was made with just 8 solar icicle lights, which pointed out like a star. Of course, there’s my all-time favorite, the dancing sparkleball with chasing lights.
You can also create a new effect by mixing lights. Just insert two or more different kinds together. (Try mixing incandescents and LED’s.) Make sure you know how the strands connect to each other before threading. One last tip: paperclip the two halves together to plug in and test the effect before you staple, so it’s easier to make changes.