Correct usage for "all you need is/are..." [duplicate]
I think the choice is driven by semantics. It depends on whether the object of the sentence is "seen" by the subject as a single concept or not.
- All I need is cigarettes and alcohol.
...if you're thinking of their desired effects on your body, but...
- All I need are cigarettes and alcohol.
...if you're making a shopping list.
- All you need is paintbrushes and paint.
...to begin your artistic career, but...
- All you need are paintbrushes and paint.
...because you already have an easel.
- All you need is friends.
...some random collection of them, that is, but...
- All you need are friends.
...each of them unique.
Finally,
- All you need is love.
...never are, but some may think they need more. :)