Uganda's banking system is backward. Credit cards can only be used in a few banks, almost all in Kampala. Travelers cheques are a ripoff and can be used in very few places. Euro's and dollars can easily be changed at reasonable rates in all towns. So my advise is to come with cash. In case you want to limit the amount you carry, you can receive more cash in many places by Moneygram or Western Union within 15 minutes from anywhere in the world at reasonable rates.