How could Reagan possibly not make the conservative list? Is that because he has been promoted from merely ex-president to god? I'd also expect to see Kennedy and Clinton on any liberal top ten list, and perhaps even Obama. I mean he comes in 14th in aggregate rankings.. I can't imagine many such lists match up with whichever one wikipedia used here.
aha! I found out why... your list is taken from a single poll done in 1982. Slightly before Kennedy had officially been deified by liberals, and before conservatives had done the same to Reagan. Also, obviously, well before Clinton or Obama.
You can easily find a Wikipedia page on the subject if you google "Historical Rankings of US Presidents." I've also made a quiz on the subject, incorporating the latest poll from last month.