For a first time curry eater, I would recommend a Bhuna or a Dupiaza. A little bit spicy, but not overly so, and not so sweet as a Korma or Kashmiri.
I find Dhansaks to be my 'tester' curry when I try out a new Curry House.
I get:
Prawn Puree
Lamb Tikka Dhansak
Sag Paneer
Garlic Nan
From any new place as my benchmark!
Having eaten a few of them I find Dhansaks have the most range from non-spicy to spicy, with some just above Korma, and others right up past Madras for heat. The variety makes it exciting!
I used to be a proper Chili head and ate very hot curries regularly, but now I stick to the more middle of the road flavoursome ones. I like Kormas, though I often find them too rich and can't eat a whole one.