I started out on straight needles, which are great to learn on before jumping on the circular bandwagon.
For a beginner I am going to recommend you stick with the straight needles until you learn your stitches and sides better. Once you are knitting the knits and purling the purls and know which is the right side of your project at a glance, then I highly recommend switching over to circs because they are easy to carry around and are just so comfy in your hands.
Let us know how you're coming along. The wealth of knowledge here is amazing.