New Delhi Palam:
I am told that New Delhi will be getting a new domestic terminal by 2008. It will be situated between terminals 1A and 1B. I look forward to it.
Yetimeter: 
Like Mumbai, Delhi too has 2 different terminals.
Terminal 1A:
This terminal hosts KF and Indian. Everything else goes to 1B.
1A is well laid lout, fairly clean and systematic. Expect a long walk between counters and is is faily expansive.
The Airport itself is OK at best. There is a 5 star lounge on the right, but they have a snack buffet (chicken tikka, sandwiches and salad) for about 500 bucks a head. No MasterCard benefits.
Post sec check there is a large waiting room with a few mini-shops scattered around. High ceiling and comfortable chairs that can be a little tattered. A few salt water fish tanks around with tropical fish and sponges. It's not bad, but sure as hell doesn't feel like the country's capital.
Terminal 1B: Hosts everyone else and frankly is a many rungs lower than 1A.
It's crowded and busy and dirty. Ceilings are low and patchy, too many flights, everything is overworked.
Look for the Himachal Pradesh counter at 1B. They sell glasses of outstanding apple juice and some great tomato soup, very reasonably priced.
One visit to this terminal and you'll know why New Delhi needs a new terminal.