I need nothing more

Felicity. I need nothing more. Ok, ok,

illimitable,
immeasurable,
imperishable,
immense,
immortal,
immutable,
incalculable
incessant,
indestructible,
infinite,
interminable,
interminate

felicity, to be frank. :P
(And conclusion - as you can see, I like letter "i" ;)