I was thinking of using poetry rather than writing my own vows (haven’t discussed this with the fiance yet). I know the Dopers will have some excellent recommendations. 
Specifically I’m looking for poems written in the first person, addressed to the lover (my favorite at the moment is the sonnet that starts with “When in disgrace with fortune and men’s eyes . . .”). Nothing too racy, please, my grandmother will be attending. 
May I suggest you not use poetry as your vows. Very few people can pull off poetry well in public (even professional actors and speakers). You may be wonderful, but your soon to be spouse may well fall short of your talent, especially with the added pressure of a wedding, audience and the general pressure of all the trappings. Also, if one is very good, the other could easily fall markedly short in comparison…Not necessarily something you want to advertise at a wedding.
I guess that ends all my ideas with poetry including the word Nantucket.
I don’t know about using poetry for the vows themselves, but when I got married we had 2 poems read in the ceremony. They were:
Sir Philip Sidney, My true love hath my heart
Ogden Nash, Tin Wedding Whistle (this meets your criterion of first person addressing second person; it’s funny, too)
Each was read by one of my sisters, and both went over well.
For ours, we had my friend read Donne’s The Good Morrow. Still one of my favorites.
When I married my now-ex, we didn’t use poetry as our vows, but we had two readings during the service. One was e e cummings:
and the other was Rumi:
http://persweb.wabash.edu/facstaff/hulenp/sperit/poetry/rumi/inthearc.html
Still my favorite two love poems.
Congratulations on your wedding. 
I’m sure the people at my wedding don’t care how “well” we read our vows. I don’t care about “pulling off” the poem. It’s just that I don’t have the confidence to write vows that aren’t going to sound cheesy. I have trouble expressing my true feelings in a way that doesn’t sound stilted and artificial (to my own ears anyway) so I’d rather use the words of those who are far more talented at expression such emotions than I am.
I might suggest to him that use traditional Irish vows instead. I found two that I liked:
Ye are Blood of my Blood, and Bone of my Bone.
I give ye my Body, that we Two might be One.
I give ye my Spirit, `til our Life shall be Done.
You cannon possess me for I belong to myself
But while we both wish it, I give you that which is mine to give
You cannon command me, for I am a free person
But I shall serve you in those ways you require
and the honeycomb will taste sweeter coming from my hand.
And:
I vow you the first cut of my meat, the first sip of my wine,
from this day it shall only your name I cry out in the night
and into your eyes that I smile each morning;
I shall be a shield for you back as you are for mine,
no shall a grievous word be spoken about us,
for our marriage is sacred between us and no stranger shall hear my grievance.
Above and beyond this, I will cherish and honor you through this life
and into the next.
(The line about crying out his name in the night sounds a bit bawdy, but maybe we could get away with it, haha.)
Thanks for the recommendations everyone. 
I like that second one.