If you haven't done so yet, look at the CD thread that is going on now. There are some good rates available.
With that much money in savings, I would move a good portion of it to some sort of CD as a safe short term investment vehicle.
Here is a primer on a CD ladder. Although, I would only do a ladder if there is a chance you might need the money that is invested in the CD. If you can put a chunk away for the 3 years and know you won't need it, then just get a 3 year CD and be done with it.
http://www.bankrate.com/brm/news/sav...1.asp?caret=14
Just as an idea, if you can do with leaving your savings at 20k (again assuming you won't have any huge bills, payments or emergencies) if you can get 80k into a CD at 6% (which is a rate discussed in the CD thread)
After 3 years (assuming you reinvest your yearly interest into another CD of at least 5% that will mature at the same time as the original 3yr CD) Your 80k will grow to more than 95k.