Depends on what you like to collect, or if you save the coppers...hoard.
Personally, I toss back most of the memorial coppers as its not worth my time to pick out. The only exceptions are I will save AU coppers when I see them, or if a bag is mainly copper and I only have to pick out a few zincolns, then I may keep them. The extra time needed to read every date since I hand sort just isn't worth the payback to me and with the number of pennies I go through, it would cut into my CRH budget pretty good unless I had a reliable easy way to sell them.
possibilities include...
* wheats and older (easy choices for most)
* Odd ball hard to find memorials... 1960 small date and 1970-S small date
* proof coins (not many penny proofs found in circulation)
* coppers (pre-1983)
* Canadian/foreign coins (depending on where you live you may find large volumes of Canadian coins)
* Error coins (potentially very time consuming to look for, depending on how you search)
* Lincoln cents counterpunched with different states or other various symbols such as a likeness of JFK or the liberty bell...
* Coins with holes in them (not valuable since they have officially been damaged, but I think I know of at least one person who collects such things...making the holes yourself doesn't count)
Anything else I forgot?