While the music of your wedding is completely personal, and should reflect the mood and tone that you want to create, here are some suggestions.  Remember, many of these songs and tunes can be used at any point in your ceremony, not just for how they are indicated.

Honor or Family Seating:
Kean O'Hara, Third Air - O'Carolan
The Gentle Maiden (this is also a lovely processional) - Old Celtic Tune
Inisheer - (this is also a lovely processional) - Irish
St. Anthony Chorale - Haydn
Greensleeves - Traditional

Processional (Wedding Party or Bridal Procession):
Bridal Chorus (Here Comes the Bride) - Wagner
Canon in D - Pachelbel
Claire De Lune - Debussy
Jesu, Joy of Man's Desiring - Bach
Dance of The Blessed Spirits - Von Gluck
Finale from "Music for the Royal Fireworks" - Handel
Give Me Your Hand - Irish
A Thousand Years; Music from the Twilight Saga, "Breaking Dawn" - Christina Perri
Colors of the Wind from "Pocohontas" - Menken
Somewhere In Time from the movie "Somewhere In        Time" - John Barry
When You Say Nothing At All - Don Schlitz and Paul Overstreet (also beautiful ceremony music)
Perfect - Ed Sheeran

Ceremony:
Ur-Chill A Chreagan -  Welsh
Eleanor Plunkett - O'Carolan
Searching For Lambs - Traditional Celtic
Hallelujah - Cohen (Jeff Buckley sings a popular version of this)

Recessionals:
Mairi's Wedding - Traditional Irish
The Royal Dream - Traditional Celtic
Ode To Joy - Beethoven
Gillekrankie - Irish
Charles O'Conor - O'Carolan
Trumpet Tune - Purcell