Shared experience and a certain mutual affinity/attraction is all that is needed for a good friendship; everything in this arena can be reduced to those two things. This is why old friends, with whom one has the most shared experience, are usually the best friends of all.

I would choose empathy because if I am feeling depressed and down I want my friend to understand,not want to go out and have fun without me or give me a lecture about morals.

All qualities you mentioned are really important my friend.

But let me please to add one more.

" Respect "

If you want any relationship -not just friendship- to last forever, just keep respect.

Respect -Give2Get-

Sincerity of course

the only quality that EVERY relation too be successful is Sincerity

people may don't need friends for sympathy or may differ in their moral values

may have different definitions to the word (fun)

and they can accommdate of doing their stuff with no need of co-operation

but even criminals and whores need someone to be sincere to them so they can feel comfortable around as sincerity includes a part of accepting the other as he is

I'm with Ruthi on this; I think empathy comes first.