It's been a long debate in this country who should and who should not have voting rights. Felons should have voting rights as long as they meet the other voting criteria. Being convicted as a felon means an individual made a (sometimes big) mistake, it does not mean they're no longer a valid citizen of the United States.
Now obviously we don't want felons who are currently serving time in prison or on probation to be casting ballots, that would lead to all sorts of problems. But once they've served their time and paid their debt to society, I believe that we ought to re-enfranchise them as much as possible, and that includes restoring the right to vote. Just because you make a mistake doesn't mean you should always suffer lifetime consequences.