Copper Penny

The Ultimate look of a cent, regardless of it's age is to have it in as high mintstate and as "red" as possible. That is what collectors of cents or who specialize in cents covet.
Obviously if you can afford nice cents and cost is not and issue, then look for MS-64/65 grades with a minimum of 85% red. The next step down from this would be MS-63/64 with a minimum of 70% red.
Next step down from this would be MS-62/63 with a minimum of 60% red.
Premium coins with high grades and blast red usually go for above the estimates in auctions and are most sought after by cent collectors.
However, the bottom line is go with your budget, and what you feel to be good eye appeal prior to making any purchase.

Glenn

If a cent was minted, oh, lets say tomorrow it would be fresh and brightly coloured, that would be considered a red, however over a short period of time if you touched it with your hands the acid on your fingers would turn the coin dark brown or almost black it would then no longer be cosidered a red.