I really don't have a favorite poet, nor have I ever "studied" poetry. I just like it. I do own some books from some famous authors like Yeats and Whitman. But there's stuff from others that I adore just as much.
Though Whitman seems to acquire some degree of taste, I do like a lot of his work. Especially Fields of Grass. But then, most people know of this book and have read it or owned it at one point in their life.
Other than Oh Captain, My Captain, here are a few of his that I really like.
O You Whom I Often and Silently Come
O you whom I often and silently come where you are that I may be with you,
As I walk by your side or sit near,
or remain in the same room with you,
Little you know the subtle electric fire that for your sake is playing within me.
Sometimes with One I Love
Sometimes with one I love I fill myself with rage for fear I effuse unreturn'd love,
But now I think there is no unreturn'd love,
the pay is certain one way or another,
(I loved a certain person ardently and my love was not return'd, Yet out of that I have written these songs.)
O Me! O Life!
O me! O life! of the questions of these recurring,
Of the endless trains of the faithless,
of cities fill'd with the foolish,
Of myself forever reproaching myself,
(for who more foolish than I, and who more faithless?)
Of eyes that vainly crave the light,
of the objects mean,
of the struggle ever renew'd,
Of the poor results of all,
of the plodding and sordid crowds I see around me,
Of the empty and useless years of the rest,
with the rest me intertwined,
O me! so sad, recurring—What good amid these, O me, O life?
Answer. That you are here—that life exists and identity, That the powerful play goes on, and you may contribute a verse.
Only themselves understand themselves and the like of themselves,
As souls only understand souls.