I'm very far from an expert, however IMHO it seems to me that the following state quarters might be worth saving if you find them XF - BU condition:
Delaware 1999 D Pennsylvania 1999- both P & D Georgia 1999 - both P & D New Hampshire 2000-P Maine 2003 D Wisconsin 2004 D (also, obviously, the 2 extra leaf varieties) Idaho 2007 - both P & D Montana 2007 P
(Possibly all 1999s & 2000s if the coins are in really nice condition (close to BU).
The above list is just my 'guesstimate' based on some 'dealer' asking prices I have seen and should not be considered as a 'guide', only as an 'opinion'.
Of course, silver proofs have value, specially the 1999s.
I don't think there is a huge interest in circulated coins. BU rolls bring the money for the coins listed:
1999 Georgia P and D over $45 a roll 1999 Connecticut P and D over $26 a roll 2002 Tennesee P and D close to $40 a roll 2003 Illinios P and D $42 a roll
My guess is none of the State Quarters will be worth much in the near future. There are way to many people that have hoarded thousands and thousands of them in uncirculated grades. And there are way to many Minted. I remember the Bicentennial Quarters in the middle 70's. I fell into that one saving them for the future. Now is that future and they are basically worth about $0.25 each.