As any fan of poetry will admit, Wordsworth is perhaps the central figure of poetry of the last two hundred years-- only Whitman contends with him in eminence. I love both (though I am partial to Keats!), and the fame of each is very just and in proportion with their merits.
Wordsworth is a musical poet, in that his verse flows with a beauty of language that has no rival I have yet encountered save perhaps Yeats or Shakespeare. Even the latter two, though better poets than Wordsworth overall in my opinion, fall slightly short of his music. I find many of his poems very easy to commit to memory, because of this quality:
She dwelt among th'untrodden ways
Beside the springs of Dove.
A maid whom there were none the praise
And very few to love.
A violet by a mossy stone
Half hidden from the eye--
Fair, as a star when only one
Is shining in the sky.
She lived unknown and few could know
When Lucy ceased to be;
But she is in her grave, and Oh!
The difference to me.
That is from memory, and I memorized it almost effortlessly; I suspect most can do the same because this poem (one of Wordsworth's "Lucy Poems", some of the best in all literature!) has a certain rhythm and flow to it that makes it as easily committed to memory as song lyrics.
There is in Wordsworth's poems a wonderful depth of thought, as well; common themes include lost youth, nature, and the poet's own mind (Wordsworth was notoriously egotistical). I find him a sadder poet than others do-- many read him as almost superficial or happy and joyous in nature, but I think this is too simplistic, as his poems resonate with a certain loss and regretful inwardness that really reverberates in my mind.
He is commonly considered the greatest of the Romantics, a consensus with which I disagree. I prefer Keats and Blake (Coleridge might have been as good, had he written more!), but Wordsworth has been more of an influence on later poets than either, and I certainly do not shy from calling him among the greatest.