I find this name magnificent and powerful. Fun fact: there is a location in the video game series "The Elder Scrolls" named High Hrothgar, a monastery which the fictional Greybeards make their home.
Believe it or not but I have actually met a man called Hrothgar. Such a pleasant surprise! I reckoned the name has been completely out of use for centuries. I like it a lot.
According to a note in "Beowulf" (translation by Seamus Heaney), Hrothgar is a combination of words meaning 'glory' and 'spear'. 'Gar' means 'spear' in Old English.