another view gave very good advice on the tripod
Because you would be assured of a steady camera for the longer exsposure times. I have had very good luck hand holding my camera but a tripod would eliminate any possibilities of movement and would be a sure thing. I don't use long enough exsposures that I can't hand hold mine.
I would definitely try at least a few at 1/30 and 1/15 to see if you like it. The longer exposures just seem to get to much of a light trail for my taste. Try several and see what stikes YOUR fancey.
Be sure and keep up with your exsposure settings (Speed and F stop) for the different shots so when you get your pictures back you will know what to use to get the effect you want the next time. :cool: