As stated earlier if you have 20% to put down and a credit score greater than or equal to 740, then conventional would be your best option. Otherwise the best choice is USDA.
USDA does have 2 limitations:
1. Property eligibility. The property must be located in a eligible area. You can check this out at: http://eligibility.sc.egov.usda.gov/eligibility/welcomeAction.do
click on Single Family Housing in the Property Eligibility section, click Accept, then narrow by State, and area, or type in the property location.
2. Income. The total household income is used, even if someone in the household is not on the loan. The income limits can be found on the same website, under income limits, guaranteed. There is a deduction for household income for Child Care expenses (for those 12 and under of the actual amount), and $480 per year for each member 18 or younger, disabled or full time student.
USDA allows for 100% financing based off the appraised value (some lenders have overlays not allowing this) which means that you could even potentially finance the closing costs as well. You can also have the seller pay for closings costs as well.
USDA is a 30 year fixed rate, no mortgage insurance, 100% loan to value, at a low rate.