Songs about losing a friend?

Hey, guys. I need some input from you all. On July 2, 1992, one of my closest friends was murdered. Anyway, this year marks 15 years since his death and I'm planning a special commemoration at his graveside including playing a special CD that I plan on making. Included on the CD will be his favorite song "What a Wonderful World" but I would like to put some more special songs about the loss of a friend, saying goodbye, or missing someone. If you all have some ideas about what to put on the CD, please please let me know. I need it by July 6th at the latest since that is the day I will be doing this.
Thank you.

I'm sorry about your friend, I guess it's a scar that will never heal.

The first song that comes to mind for me is perhaps a quite abvious choice, Tears in Heaven, Eric Clapton. Maybe I'll think of something else later, in that case I'll tell.

How Can I Help You Say Goodbye - Patty Loveless

One of the most beautiful songs.

Without You - from the musical RENT

Come Some Rainy Day by Wynonna is a beautiful song that might be appropriate. It will make you cry though.

Artist/Band: Wynonna Judd
Lyrics for Song: Come Some Rainy Day
Lyrics for Album: The Other Side
(Billy Kirsch/Bat McGrath)

What good's a dollar
Without your baby sister?
Two scoops of ice cream
On a summer afternoon
We ran wild
And all we ever wanted
Was to rule the world
Between our house and school

We move on
Put those dreams away
Thinking that we'll find them
Come some rainy day

First time I saw you
I knew I would love you
Half way through sophomore year
I finally asked your name
When I kissed you
I lost my heart completely
All we wanted
Was just to stay that way

We move on
Put those dreams away
Hoping that we'll find them
Come some rainy day
How could I know
That everything would change
Except the way I miss you
Come some rainy day

I'll sit and laugh with friends
At what we've all been through
But I still catch my breath
When someone mentions you

We move on
Put those dreams away
Thinking that we'll find them
Come some rainy day

Judd Wynonna - Come Some Rainy Day Lyrics

I just thought of another one. "One Sweet Day"

I immediately thought of Missing You by Diana Ross. I believe she sang it to Marvin Gaye after he died.

I also just thought of "Hard To Say Goodbye" by Boyz II Men

One sweet day by Mariah Carey....they played it at a funeral of one of my friends and there wasn't a dry eye in the house. :crying

"My Old Friend" by Tim McGraw is also a good one

Good Riddance (Time of Your Life) by Green Day