Ah, a tricky one, this.
The Catechism of the Catholic Church (thanks for the electronic reference, Simon-Peter - my hard copy is still in a packing box with all my other books) tells us that "'The Lord's name is holy.' For this reason man must not abuse it. He must keep it in mind in silent, loving adoration. He will not introduce it into his own speech except to bless, praise, and glorify it.
Respect for his name is an expression of the respect owed to the mystery of God himself and to the whole sacred reality it evokes."
The Second Commandment prescribes respect for the Lord's name.
And yet, when I was at school (a convent, by the way), we were punished for using four-letter words, but not for taking the Lord's name in vain - and this fostered the attitude that blaspheming was not as "bad" or socially unacceptable as using the names of bodily parts or functions.
I do make a conscious effort now to use other words - "golly", "gosh", "blimey", "wow" - and to keep the Lord's name holy and use it only with respect. But unless there's been a drastic change since my day, I think our Catholic schools are failing young people in not impressing on them the gravity of this casual blasphemy.
For myself, all I can do is acknowledge past faults and try now to set a good example to my nephews, nieces and godchildren (and one day, Deo volente, to my own children), and continue to praise, bless and glorify the Lord's name.