Historical plates in Ohio are the best deal, because you pay a small one time fee ($15?) and there is no annual renewal. You pay the $15 and you're good to go until 2050.
There's been talk before about the legalities- only supposed to use them while going to or from parades or functions. However, I've been riding on them since 1996 and never had an issue. I've been pulled over twice for speeding and it wasn't even brought up. The speeding was however lol.