XNA Game Studio Express
It's better, if possible to use one sprite batch. The amount of sprite batch start and end calls will be one of the biggest performance impacts in your 2D game. The next big performance tip is to use as few Texture2Ds as possible, and if you have multiple sprites coming from the same Texture2D, draw all those sprites in sequence then move on to your next texture since each time you switch the texture you are drawing from there is significant overhead. Ideally you would have all of your sprite graphics in a single texture, but at least limit it if possible.
Bill