For now,Id worry more about lesser known newer fights.
When you guy watch a guy like even Ali,it may be entertaining,but you probably cant do that yourself. Or if you go back to Jack Dempsey,again its entertaining,but the sport has evolved alot since then.
Id stick with stuff like Vazquez/Hernandez and stuff on that level,the all time greats are great because they could do stuff other guys couldnt,watch tape on how to make yourself solid first.