Ultimate in gifts, and best card? (6)
I believe the answer is:
scream
'card?' is the definition.
(both can mean a humorous or entertaining person)
'ultimate in gifts and best' is the wordplay.
'ultimate in' suggests the final letters.
'and' is a charade indicator (letters next to each other).
'best' becomes 'cream' (as in 'the cream of the crop').
The last letter of 'gifts' is 's'.
's'+'cream'='SCREAM'
(Other definitions for scream that I've seen before include "card" , "one causes great amusement" , "Call for" , "A long piercing cry as of terror" , "Howl, shriek" .)