Personally I like Lamb Korma, its not too spicy as in hot (although I also like spicy and hot food) and I once had a very tasty goat curry at an Indian buffet, although I would caution that much like many Chinese buffets, Indian buffet restaurants are may not have the same sort of quality as a good sit down restaurant would. Tandoori chicken is also a good dish to try your first time out if you dont want a dish that is too spicy but Ive had some very dry Tandoori chicken.
I found this link by Ian Anderson (yes of Jethro Tull) that might be helpful.
http://www.j-tull.com/musicians/iananderson/indian.html
As others have said, tell your server you are new to Indian food and ask for some suggestions telling him or her of your tolerance for hotness, then dive in and enjoy. And please let us know how it went.
BTW, I currently work with a gal who was originally from India and she sometimes brings in home cooked dishes for me to try, mostly vegetarian although she does eat chicken and fish occasionally very yummy but not what youd find in most Indian restaurants.
That Ian Anderson link is great! Good stuff. I first saw him with Tull when I was about 17, in the mid-70s.
Hey! Ian Anderson is on Coast-to-Coast tonight!