What are some good songs for a wedding ceremony/reception?

My big sister's getting married and she's always loved my musical taste. She's decided to have a small outdoor wedding and reception. She's in her late 30s and this is her first wedding. There's going to be an old and a young crowd, but more thirty, forty, and fifty somethings rather than 20s. She's asked me to handle ALL of the music from ceremony to reception. Music's not her thing, but it is mine so she says she trusts me. Her fiance doesn't care too much about music so they've basically left it up to me. I need some suggestions song wise. For the reception, she told me she wants it to be audience appropriate and a good mix of oldies, classic rock, country, and the popular stuff on radio today. I also need a song for our Mom, Dad, and a first dance song for them. I know she mentioned she would like a mash up of the first dance which I think would be cool. Help please!