I'm glad that all of you know a lot more about the wording stuff than I do... I have a quick question!  
As many previous posters, I also want to mention both the Nuptial Mass and Sacrament of Holy Matrimony in my invitation wording (as well as both of our sets of parents)... this may be splitting hairs, but is it accurate to say that the Nuptial Mass "is uniting our children" when technically we will be conferring the sacrament of Holy Matrimony upon one another (not the Mass)?  I know that the parts of the sacrament are integrated into the Nuptial Mass as a whole so I'm not sure how I should be definining them.  I'm referring to clearheaven's suggested wording that I pasted below (very very beautiful, helpful and informative planning bio, btw!!)...  TIA!  I think this is very close to what I'd like to use also.
Mr. & Mrs. [bride's parents]
&Mr. & Mrs. [groom's parents]request the honor of your presenceat the Nuptial Mass uniting their children[bride]&[groom]in the Sacrament of Holy Matrimony[date & time][church]