Did Light Actually Like L (in a friendship way)?
This might be my personal opinion, but this does not look like the face that a person would show his friend when that friend is dying. Light had been pretending to be L's friend for a while, so by (over-)reacting he achieved two things. The first would be keeping his image and the second would be giving him a reason to go looking for the Death Note, that he knew would be laying around somewhere.