Pretty sure there is revisionist history available regarding Richard III. He died fighting gamely in battle. Not that that excuses any murderous acts on his part, if he was actually guilty of such. But his reign and how he came to be in the position he found himself in are probably known more clearly now. The bloke who userped him had a very tenuous link to the throne and produced his own monster, the bloated tyrant Henry Viii.
As a disgraced man with a string of ex-wives, I have some empathy for Henry VIII. I wish I could have had two or three of them beheaded. Plus by setting up a national catholic church independent of Rome, he started the process that turned England into a distinctive and separate nation, semi-detached from Europe.
However I think my favourite post-Conquest king is Richard I (the Lionheart), based on the mythological history I have read. I prefer the Old English [pre-Conquest] kings and chiefs really, but that's perhaps a whole other topic.
Back in school, they used to make us sing that mnemonic rhyme with all the kings and queens, which means I can recite every one, and most of the dates too.
In my opinion:
The greatest king overall was Henry V.
The most heroic king [post-Conquest] was Richard I - Cœur de Lion.
The most competent king was William the Conqueror, with Henry II close behind.
The most important king of the modern era was William III/II (William of Orange).
The worst is the present one, Elizabeth II, or Elizabeth the Worst, as she is sometimes nicknamed.