Our impression of Delhi from our first three days here was that it was a place we did not want to be. Our flight home leaves from here, and we had purposely avoided Delhi until we couldn't put it off any longer. Before coming to India, several people warned us that we would not enjoy ourselves - "It's not if you get sick but when," "rickshaw drivers won't take you where you want to go," "all official government tourist offices are fake," "the traffic is nuts" and "the hotels are filthy and infested with bedbugs and cockroaches." Luckily, we found that most of India was very pleasant and we thought that these warnings must be exagerations. Then, we came to Delhi. It is easy to understand why someone wouldn't like India if they started in Delhi. The whole tourist industry here (shops, sights, hotels, rickshaws) seems intent on getting the most money possible from you now, with no consideration that you might ever return.
Still, if you are ever unlucky enough to spend time in Delhi, we have a few recommendations. Visit Old Delhi for a taste of local life and an escape from the hassles of tourist markets (Marieke especially recommends the wholesale spice market).
Go see the Lotus Temple, a beautiful Bahai temple.
And, go see the Sulabh International Museum of Toilets. Seriously. The museum itself was well-run and interactive, but the most interesting part was learning about the works of the Sulabh charity. They are dedicated to improving the designs of toilets in India, for many reasons. They are improving sanitation and health. They are reducing pollution. They are creating low-cost alternatives so that even the poorest villages can have toilets. They are reducing water consumption. They are improving the lives of over 600,000 "scavengers" - members of a lower-class (called Untouchables) who clean out pit-toilets and transport the waste. They are generating electricity from biogas and using composted waste as manure. All this, just by rethinking the toilet... It was a humbling experience to think how much waste our toilets back home actually generate.