Many scholas are looking now to the Introit as a way of re-solemnizing the Mass, and it is an excellent place to begin. To use the proper text, ideally with the Gregorian melody, but suitably with other options, is a way of setting the right tone for the Mass at the very outset.
Some years ago, people began to turn to Lent as a season for introducing the Latin text for the Ordinary. It is now time to do the same as regards the propers. No matter what hymn you happen to choose as a replacement for the proper, it will not quite achieve what the musical form intrinsic to the rite can achieve. The best way to see this and understand this is to experience it. A solemn entrance is the musical foundation of everything that follows.
Before going through the various options, let me first address what is in fact a common view that it is not appropriate that a parish (as versus as a monastery) use the proper as the entrance. Rather, it is believed, parishes should sing hymns. It is hard to know where this idea originates; it probably reflects a judgment rooted in conventional praxis. What is striking, however, is that there is no evidence at all that that this was the intention either of the Second Vatican Council or the promulgation of the 1970 Missal.
Here is what the General Instruction says: "After the people have gathered, the Entrance chant begins as the priest enters with the deacon and ministers. The purpose of this chant is to open the celebration, foster the unity of those who have been gathered, introduce their thoughts to the mystery of the liturgical season or festivity, and accompany the procession of the priest and ministers."
And what music? The first and clearly most preferred option is the one deeply rooted in Roman Rite tradition: the antiphon and Psalm from the Roman Gradual.
The English text for the first Sunday of Lent is: "When he calls to me, I will answer him; I will rescue him and honor him; with long life will I satisfy him."
From the Gregorian Missal:
Let me say here again, just because people seem very confused, this is the normative ideal for both the old and new forms of the Roman Rite. This applies as to the 1962 Missal as to the 1970 Missal. This is not disputed as regards the 1962 Missal. But it remains true in the modern Missal as well. This chant belongs in the ordinary form, the Novus Ordo, the Mass of Paul VI, the Mass heard in 95% of Catholic settings in the English-speaking world, the current Missal after postconciliar reforms--please fill in any formulations I've left out. This is the entrance chant for the first Sunday in Lent.
The question is inevitable: why is it that we don't tend to hear this? Why do we not even hear that it is an option, much less the ideal? Those are interesting questions, and I'm not going into here. Rather, the purpose here is only to entice music directors to turn to our tradition as a means of being truer to the liturgical structure. There is no question that matters are changing in any case, with ever more parishes turning to propers as a way around the endless and mundane controversies over hymns.
Now, it is possible to sing other versions besides the Gregorian version. The text can be sung in English as well, in plainchant. This preserves the upward and forward motion of the Gregorian song, and avoids the "four on the floor" beat of the metered hymn. There is merit, too, to singing the actual words of the proper text, if only because it means that the Mass itself is integrated into the music being sung, so that the music is not merely accompaniment.
Here are some readily available possibilities.
From Fr. Samuel Weber:
From the American Gradual (Bruce Ford):
From the Complete English Propers (Abrogast):
From Fr. Columba Kelly:
From the Anglican Use Gradual:
If nothing else, there are always the Rossini propers:
Even given all of this--and everything here is completely free--I've probably left some possibilities out here.
The main point is to progress toward a truer liturgical experience than merely selecting something from the hymn grab bag.