It depends on your tolerance for risk, how much access you have to have to the money, etc. For straight savings, some Flutherites have used ING Direct, a Web bank that pays higher interest rates. It is FDIC insured.
Check out bankrate.com for up-to-date info on the highest interest rates for money market accounts and high-interest savings from tons of banks. The best deal tends to change week-by-week. Plus, bankrate seems unbiased.
My fave short term stuff (less than 2 years) are CD’s (certificates of deposit). Banks are always throwing out good rates on varying length CD’s. I recently got one for 6 months at 4.5% which is a rate you’d get for an 18 month or longer. Shop around. The only negative is that your money is locked for the term of the note. Have fun shopping!