Guess I'm late getting on this one! Anyway, what the hey here's my plants wishlist:
Nepenthes: N. edwardsiana (the true), N. klossii, N. platychilla, N. papuana (I may have it as Doorman's Top #2, Irian Jaya but nobody knows what this is exactly yet), N. dubia, N. tenuis...
And for my Aroid collection of course I must acquire:
Amorphophallus titanum (with a 6-10 ft inflorescence and bulb/tuber of 170lbs)
Arisaema griffithii (the Cobra Lily of the Jack in the Pulpit scene)
Alocasia robusta (world largest undivided leaves)
I'm always looking for new Pleurothallid alliance orchids (Dracula, Porroglossum, Restrepia...) I love those little guys!
I'm sure there are more but I can not think of them all. The main "most wanted" thing for me is a greenhouse. I want to be able to have two climates inside highland and lowland and I want to decorate it like a jungle with landscaping and plants growing "naturally" inground or in hidden pots. I guess I'm saying I won't be happy without my own botanical garden!