It seems the in thing is to have everyone walk down the aisle to different songs -- one song for the groomsmen, a different one for the maids, and yet a different one for the bride.
Anyone planning to have just one song for the entire wedding party and the bride and groom?
Re: Processional
You can have two separate pieces for the bridal party if you really want to, or you can just have the volume turned up when it is time for the bride to enter. I played a 100 year old pipe organ in my last job, and when I hit the button, it really blasted that bridal chorus! If you are using canned music this is more difficult.
One reason that the Canon in D is so popular for weddings is that it can be as short or as long as required. It can go for ten minutes, or just one round, though that was not Pachelbel's intention. It is not religious music, but it is used in both secular and religious weddings. Very practical.
To address @missa011's comment, Catholic weddings have very strict rules about what music may be used.