In reply to TheDrunkenBakers:
My partner is Asian (Sri Lankan) and I lived with her family for many years, as well as travelling all over the subcontinent, so I've had a fair few home made "authentic" curries - lunch today was rice, a daal, pumpkin curry, shredded kathurumurunga and a masala omelette.
Some thoughts:
Cooking good South Asian food is really hard. I think it takes a lot of practice and experimentation. Everyone who is grinding their own spices, yes this is the way forward and hats off to you.
Don't be afraid of using spice. If we go to a curry house that's clearly for white people (most of Brick Lane, for example) then to us it's pretty bland, we don't necessarily like everything hot - different families seem to have different tastes - but it needs to taste of something! The umami element is really important too, particularly in South Indian or Sri Lankan food, probably due to the use of a lot of fish. You're aiming for that full, round, very satisfying experience in the mouth when you come to the end of the meal.
Don't use chilli powder too much. Chillies are much better, or for a really good heat, use black pepper. Curry leaves are important in southern cooking (don't eat them) as is coconut milk. We very rarely use ghee, in fact I'm not sure we even have any in the house.
English people tend to order rice and a curry. Basically meat and a bit of veg approach, but desi-fied. Aim instead for as many dishes as you can, for example if we cook rice and curry at home then we'll have a minimum of two, say some lentils and a paneer or fish dish, but that's just a time saving thing. A proper dinner should have at least four or five! That way you can have a hot dish, a dry dish, something with a lot of gravy (say from coconut milk), maybe a piece of fried fish or a meat dish (remember that most of our family gatherings span the range from strict vegetarians to meat lovers). Sri Lankans eat smaller, slightly thicker popadums but not as a starter, with the main meal. This is really good for getting some crunch into your dinner. They also do deep fried chillies, which you can buy in Tamil shops (might be hard outside London), I think they process them with yoghurt to take off some of the heat, very nice for a special occasion. Curried omelettes are easy and lovely too, either with dinner or on their own.
Get a rice cooker!