Yes, Daniel Day Lewis is one of my favorite actors too, though some of his very few roles feel similar in their natures (probably why he is able to play those roles well). My Left Foot is one of my favorite films. There Will Be Blood should have won that year IMO. Last of the Mohicans was a solid one, though not what I'd call a great character for him so much, but I loved the film.
Oldman has countless great performances, even small ones, and is also one of my favorites. It just surprised me that he hadn't won.