When it comes time to choose the specific music for your processionals the options used to be very limited. The same half dozen classical standards were recycled wedding after wedding: Pachelbel's Canon, Jesu, Joy of Man's Desiring by Bach, The Trumpet Voluntary and Tune, Water Music, and Ave Maria, the Wedding March and the Bridal Chorus. The rise of the internet, changes in social media, and new technologies now allow an almost unlimited variety of music that can allow each bride to choose truly individual music.
A brief list of some recent processionals have included "Dream" by Priscilla Ahn, "The Book of Love" by Peter Gabriel, "Chasing Cars" by Snow Patrol, "Wonderful Tonight" by Eric Clapton, "Isn't She Lovely" by Stevie Wonder, "Here Comes the Sun" and so on as well as a few pieces composed specifically for the bride by their musical friends.
Themes from television and the movies are frequently incorporated into the ceremony as well. We have even played some of the music from the HBO drama "Game of Thrones" for recessionals including music played at the "Red Wedding" which while stirring might have been taking things to an extreme! The main thing to remember is that options are no longer limited. It is good to consider that are challenges to using contemporary music for processionals. The traditional classical pieces became "traditional" because they were structured so that stopping places could easily be found every ten or fifteen seconds or so which allowed the musician or musicians to bring the music to a satisfying close when the final bridesmaid or the bride herself had reached the front of the church. Contemporary music is rarely structured that way and it takes skill to either modify an existing arrangement or simply be able to improvise an ending that will allow the music to appear to have been seamlessly timed. If a group is professional in their approach and comfortable with producing custom arrangements this can work well. If the players are not experienced it is very easy for them to have an extra minute of music being played while nothing happens, or to simply fade away, or worst of all to "run out" of music.
There are of course some pieces that simply will not translate well to string instruments. Rap music, songs that rely on an extraordinary vocal styling, songs that feature electronic beats or drum intensive and distorted guitar effects often will disappoint no matter how skilled the players and the arrangement. Again an experienced group can usually listen to the song online, quickly size up the available sheet music and make a judgement as to how well the music may fit. Happily many popular artists today produce music that works well for strings - much more so than music of the 1980's for example! Adele, Bruno Mars, Coldplay, Evanescence, Edwin Sharpe, John Legend, and others almost always produce music that fits well at a wedding. So if you don't see a particular song on a group's playlist don't be shy about asking if it can be played for you! The answer may be yes more often than not.