What a good thread! I have always loved hymn singing. I grew up on the 1940 Hymnal but can't seem to find my copy.
Favorites:
Alleluia, Sing to Jesus to the tune Hyfrydol
Be thou my vision
The King of love my shepherd is to the tune St Columba
Blessed quietness (although I've never heard it sung at church!)
Amazing grace
The list goes on, but these are the top 5 for me.