Christopher said:

I love spending $2 bills. There's really no reason to save them (at least the Series 1976 and 1995 issues)--they remain a current denomination of U.S. currency, and the Bureau of Engraving and Printing will print them when the supply runs low (which isn't very often). My bank is happy to give me whatever $2 bills they have on hand. (I haven't asked my current bank, but my previous bank was willing to order all the $2 bills I wanted.)

One time I nearly caused a fast-food cashier's brain to crash by giving him, among other things, a $2 bill, a half dollar coin, and a dollar coin.

(Note for those of you outside the U.S.: the above denominations don't circulate much here.)