Delhi is by far the most polluted city I have ever been to. I have no respiratory sensitivities, yet I found myself having a tough time breathing.
The airport is nice, though immigration is slow. I was intrigued by the duty free shop beside the luggage carousels to get a last fix of extremely cheap booze (this is as cheap as it gets for worldwide brands). On the way to immigration, you can see a very nice cigar store, but it is apparently inaccessible for incoming passengers. Changing money is easy with low commissions by Western standards. Getting a taxi into town is a bit of a hassle. There are numerous "fake" prepaid taxi stands outside of immigration (before you reach the hordes of touts, etc.). They start negotiating at 1200 rupees ($30), though quickly knock down to $15. However, if you go outside to the police prepaid taxi stand and firmly ask, you can get into town for $5.
The Ashok Hotel (formerly the Ashoka -- many taxi drivers, etc. still use this name). Surprisingly, the website can't be found using Google (though this post will change that). It is owned by the national tourism board. The only thing they would sell a foreigner is a suite (once local, there was minimal additional cost of a suite over a basic room). While the layout had potential (big rooms, nice refrigerator), the condition of the room was horrible. Large stains in the carpet, extremely dark and dingy, furniture old and decrepit. The views were terrible -- a dirty workzone. Oh, and all rooms (as are most in India) are smoking. The high-speed internet did not work, and could not be repaired (it had likely not worked for a long time). The restaurants were quite good, however, and reasonable by Western standards.
I did have a problem on checkout. I had attempted to call them from the US to arrange airport pickup. They refused as best I could make out. I then emailed them and never received a response. (Airport transfers were included in the room price). So I grabbed a taxi. When I arrived, the front desk said that a taxi driver had called looking for me. I didn't pursue the issue. At checkout, there was a 350 rupee charge on the bill for a taxi. When I asked what the charge was for, I got a great deal of confusion. They couldn't find the underlying bill. The clerk and his manager went back and forth for 20 minutes "investigating" unsuccessfully, then requesting that I pay the bill without presenting a reason for the charge. (They knew I was going to the airport for a early morning flight). Finally, I took matters into my own hands, grabbed the bill, crossed off the charge, and paid cash to settle the bill.
I'd avoid the Ashok. It is horrendously overpriced. Unfortunately, it shares this with almost all hotels in Delhi since it is a major gateway for international flights. Next time, I would look more closely at the hotels farther away from the city -- it is unbelievably cheap to hire a car and driver for the day.