Good lord there are a lot of incorrect responses in this thread.
Madhur Jaffrey has some good cookbooks with a lot of traditional, some fusion, etc. Keep in mind that the style of food varies greatly, even within states, cities, etc. Don't go into it thinking that you can capture the one and only way of preparing something.
I would get a handle on the style before just trying random recipes. Simpler dishes like a mutter paneer, from scratch, will help you get a handle on all the spices used. We have probably 50+ different spices that we use in our cooking at home. Some are more for tradition and leave little actual flavor, others provide tremendous flavor and Indian isn't the same without it; as an example, whole garam masala vs. pre-ground. The difference is incredible. Another is fresh ginger and garlic vs. ginger garlic paste.
So, I'd probably try:
1) Rajmah masala
2) Mutter paneer
3) Chole/chana masala
If you can't get those right, you won't get anything else right either.