Both answers are excellent. I have one small point to add: The effect of misusing our powers, or misdirecting our spiritual and emotional energy, is that we have created a lonely world.

The poet bemoans the spiritual disconnect we have wrought by living worldly lives. As sullymonster has said, we are too focused on materialism to be spiritual. Herin lies a paradox: we are both too immersed in the world (meaning worldy concerns) and too separated from it (meaning we've lost our spiritual connection with nature.

When the narrative persona says he's "rather be a pagan", he's not necessarily saying he wishes to revert to that time or that religion (this is evident in the fact that he calls it a "creed outworn"). What he does want, though, is to recover some of the wonder and awe that the pagans experienced in nature.

He says that were he a pagan, he would see glimpses of the gods (Proteus and Triton) that would make him feel less forlorn. To be forlorn is to feel sad and lost, to feel abandoned and alone. He uses the allusion to the gods to show us we are separated from God (in a poetic, not Christian sense), that everything is wrong (spiritually) with the way we live our lives.

What he's talking about here is the extreme spiritual and emotional isolation he (and we) have created by living worldly lives that are separated from nature. The cost to the individual is to feel forlorn: abandoned, separated, and utterly alone.

Wordsworth was expressing a feeling often connected with the average citizen in the modern age. "The world is too much with us" - most simply, we are too wrapped up in the concerns of our everyday lives, and have lost sight of what is meaningful. We are "getting and spending", we have "given our hearts away." Wordsworth also accuses humans of "lay[ing] waste to our powers", or misusing the energy we have in the pursuit of materialistic goals.

Nature is personified in this poem, raising its significance. The "Sea" is strong and rebellious, "baring her bosom to the moon." The constrast to the the weak actions of the humans further disparages the humanity and reminds the readers to return to the beauty and importance of nature.

Wordsworth makes it clear that the readers are as much to blame as the poet. "We" and "our" are the subject pronouns used. However, the poet separates himself in the end, espousing a strong desire to become of pagan culture, to worship Nature, and (as we are left to believe) to be happier as a result.

"In the sonnet "The World Is Too Much with Us" the poet contrasts Nature with the world of materialism and "making it." Because we are insensitive to the richness of Nature, we may be forfeiting our souls. To us there is nothing wonderful or mysterious about the natural world, but ancients who were pagans created a colorful mythology out of their awe of Nature."

Here is the poem, with some unfamiliar words glossed:

The world is too much with us; late and soon,
Getting and spending, we lay waste our powers;
Little we see in Nature that is ours;
We have given our hearts away, a sordid boon!
This Sea that bares her bosom to the moon,
The winds that will be howling at all hours,
And are up-gathered now like sleeping flowers,
For this, for everything, we are out of tune;
It moves us not.--Great God! I'd rather be
A Pagan suckled in a creed outworn; (1)
So might I, standing on this pleasant lea, (2)
Have glimpses that would make me less forlorn;
Have sight of Proteus (3) rising from the sea;
Or hear old Triton (4) blow his wreathed horn.

(1) Brought up in an outdated religion.
(2) Meadow.

(3) Greek sea god capable of taking many shapes.

(4) Another sea god, often depicted as trumpeting on a shell.