I think you need to think of a vibe for the introductions. Are you looking to make it fun and contemporary or, elegant and traditional? If you want to keep it fun you can play anything from Black Eye'd Peas "Let's Get it Started", Natasha Bedingfield "love like this", Madonna "4 minutes" or Classic 70's/80's like "ain't no mountain high enough", "Walking on SUnshine" etc...or you can play old school "Fly me to the moon", "Isn't it Romantic" "just the way you look tonight"
Same thing with background music..what is the feel you are going for? Old school play classics or contemp norah jones, michael buble. I think a nice mix is awesome. If you are using a deejay even consider giving him a CD of your favs ...if it is a band give the bandleader a list of song suggestions for background music.
Deanna Jones
Music At Your Wedding