My prediction is that, like has been said before, as the supply dwindles from people cashing in, the values of the nicer grades will probably climb, and lower grades will probably see more or less a flat line for years and years. I don't really see the Zincolns gaining much, at least not until they are absolutely rare, say around the year 2112 or 2212, something like that.
The penny has had a really good run, unlike the previously mentioned 2 cent, and 3 cent. In it's past the penny was a bit of a staple in the diet of the economy, it actually had some value. It definitely does not have the value that it did 70 years ago, but I know alot of people who prize their
Wheat penny hoard, simply because they're old and they don't make 'em anymore.