Going back through my lifetime:
Eisenhower, I was too young to judge at the time, but I would have liked him. He wasn't afraid to raise taxes and try to balance the budget, unlike other Republicans, and he coined the term military-industrial complex in order to warn us about its dangers--a warning we have yet to heed and therefore we do, in fact suffer under its undue influence half a century later.
Nixon--well, he kicked himself to the curb
Reagan--He was charming and witty as he sold us on the myth of trickle-down economics. I didn't want to kick him to the curb, despite his oversight of the ballooning of the national debt. At least I believe he was a fundamentally decent human being.
Bush 41--Again, he didn't represent my politics, but Democrats didn't have to kick him to the curb--- he did himself in by the end of his first term
Bush 43--Well, what can I say about a man who started a war under false pretenses and allowed the financial industry to build a house of cards that took a big chunk of prosperity and stability right out of the back end of the early years of the millennium. But even with that said, he didn't come across as pathological.
So, for me, Trump really is the one who's the scariest. I find CNN's relentless mission to get rid of him before 2020 very tiresome, and the Democrats mission to impeach him misguided, but I can't say I wouldn't love to see him kicked to the curb.
ETA: I really would have liked Teddy Roosevelt. He was a progressive Republican, and his love for nature and his achievements as a conservationist were directly in contrast to the policies of our president who would sell out the whole planet for 30 pieces of silver.