Physical beauty is not ultimately subjective. Our notions of physical beauty are often tainted and perverted by sin, but they're ultimately and objectively based on health and procreative power. Numerous studies confirm this: http://en.wikipedia.org/wiki/Physical_attractiveness.
And, particularly in Catholicism, procreative power and the act of procreation is both good and integral to marriage.
“The matrimonial covenant, by which a man and a woman establish
between themselves a partnership of the whole of life, is by its
nature ordered toward the good of the spouses and the procreation and
education of offspring; this covenant between baptized persons has
been raised by Christ the Lord to the dignity of a sacrament.” (Catechism of the Catholic Church, paragraph 1601)
And, among copious other affirmations that marriage and procreation are highly good,
Called to give life, spouses share in the creative power and
fatherhood of God. “Married couples should regard it as their proper
mission to transmit human life and to educate their children; they
should realize that they are thereby cooperating with the love of God
the Creator and are, in a certain sense, its interpreters. They will
fulfill this duty with a sense of human and Christian responsibility.” (CCC 2367)
And this is supported numerous places in the Bible as well, but most obviously in the beginning. It's the very first command and blessing given to humans.
27 God created mankind in his image; in the image of God he
created them; male and female he created them. 28 God
blessed them and God said to them: Be fertile and multiply; fill the earth and subdue it. Have dominion over the fish of the sea,
the birds of the air, and all the living things that crawl on the
earth (Genesis 1:27-28)
Here, God's first command, to be fertile and multiply, is given in the context of a blessing. And we know that beauty, however tainted our perception and treatment of it may be, is ultimately a sign of procreative power. So, right off the bat, beauty is good and arguably a blessing.
To be clear, a blessing is something which affirms or assists us in a holy or divine purpose (What does it mean to "Bless the Lord"). Beauty is an assistive recognition of our divine purpose, our first-received command, to procreate. And it is, in that respect [among others], a blessing.
As noted though, our perceptions and values are tainted by sin. We tend to hyperfocus on it, sifting it out as its own thing, rather than a single component of the mystery of creation, making an idol of it, and holding tainted, pleasure-serving perceptions of it. And for that reason, we must be careful not to hastily attribute all "beauty" to God's blessing, nor to be envious of any blessing.
All things are given by God. God gives to whom He desires. And Christ blatantly suggests at numerous times, often through parables, that our blessings are unequally distributed. The parable of the talents is a good example of this.
Like the Angels, we do well to recognize and co-bless, but not covet, those who have been blessed by God:
26 In the sixth month, the angel Gabriel was sent from God
to a town of Galilee called Nazareth, 27 to a virgin
betrothed to a man named Joseph, of the house of David, and the
virgin’s name was Mary. 28 And coming to her, he said,
“Hail, favored one! The Lord is with you.” (Luke 1:26-27)