Hmm.... For US releases, I'd say blue-heart version of Dazzleglow, M/O Sprinkles, and the Flower Fantasy ponies.
For Nirvana... Night Light, Rain Drop, German Starshine, all the Flutterbye variants (I've four right now, if I'm not mistaken), the unicorn version of Blossom (Peru? Mexico? Can't recall right now), and... French Reverse Bowtie (so pretty!). I don't even want ton know how much she's cost.
Mine was G2 Queen Sunsparkle, but I got an amazing deal for her on ebay like last year. I suppose now mine are the Apple Delight Family, the flower fantasy ponies, and the Halloween G3s (Pumpkin Tart and Abra-ca-dabra).
Pretty sure I have at least one of those two G3s MIB; can't recall which one though. I can take a look in my sales box, if you'd like?