Help! Wardrobe dilemma.

Normally my life as an author involves clothing choices. Will I wear the black jogging bottoms today or the grey? Split-second decision and move on.

However, I now have a wardrobe-related quandry and I need some help. (Husband is no help. He thinks I look nice in everything.) For this kind of thing you need girl advice.
Anyway, here’s the skinny…

I had my outfit all planned out for Harlequin’s party in New York during the RWA conference in a couple of weeks, and then when the invite arrived I discovered it was a black and white ball. Very swish. But then I realised I might need something a little more dressy than I’d been planning.

Here are the options, 1-4:
(Click the picture if you want to see it larger)

I’d been planning to wear no.1. Black, yes, but also cream animal print. Could I get away with it, and is animal print too much?

My other option was no.2. Black and white, certainly, but maybe not dressy enough? (It's not a full ball-gown affair, more cocktail dresses etc.)

Option no.3 is black, looks fairly elegant, but it’s actually a bargain buy in cotton jersey. Can be dressed up with nice accessories, though. But don't want to feel downmarket...

Option no.4: something I found in the wardrobe when I was looking for something else and forgot I'd had (hence the sandals that don't work - I shoved it on and did another photo right before I left the house to go shopping). Fits the bill, but I wore it to the HQ party in 07.

Any ideas, anyone? Anyone? Bueller…?