I actually love every Mark. perfume that's come out so far. I'd say my favourite is True Heart, but Hollywood Pink Flamingo and Karmala are close seconds. Karmala isn't as strong as I'd like but it's really nice and a good cold weather scent.
Instant Vacation is a great tropical scent without being too suntan lotion-ish (and it's subtle, which is nice). I love the smell of Hollywood Pink but the perfume fades so quickly that it's pointless to wear it. I use the lotion instead.