You'll be amazed how much your savings will go to finding a new place to stay, transportation and job hunting expenses. Have realistic expectations about the US job market. Even if the US economy is hot right now, it will take time to find a good, full-time position. You may have to do consulting work or take a part-time job when you come back to supplement your savings. Also, you are going to have to remarket yourself for the Stateside job market.
Health insurance is a necessary evil.
Horror stories about HMO's and PPO's at home can make your host country's socialized medicine system or your expatriate health insurance plan look real good. Many hospitals and health care providers in the US will NOT treat you if you do not have health insurance coverage. If your Stateside employer or university program does not offer you health insurance, you can call your state's Department of Insurance to provide you with a list of licensed health insurance brokers. Develop your own support network at home. After the initial excitement of returning to the US, you realize that your Stateside family and friends have stopped asking you about your time overseas and quickly tire of your stories of life as an expatriate.