Let's be serious. The UN failed it's mandate as with its predecessor. The USA was right not to be attached to the cancer that was the League of Doom. As for global discussions, try a phone.
Do not forget that the UN was the forum used to diffuse quite a number of Cold War tensions. (like the Cuban missile crisis).
The UN may have had significant failures in peacekeeping (i.e Rwanda) but there have been successes (e.g. Liberia, East Timor). What other platform would enable Indian troops to be involved in peacekeeping operations in Sierra Leone?
The UNDP (UN development programme) may not have much use for citizens of Western Europe and America, but it has done a great deal in the developing world.
The UN was the vehicle through which sanctions were imposed on South Africa, Zimbabwe and Burma.
Our relationship with the world is not limited to China, Western Europe and the Middle East. We cannot fulfil our foreign policy objectives for the rest of the World apart from the UN. It will be a cold day in hell before American troops get involved in any intervention in Africa. So we need the UN there.
Now I may not sound very popular in conservative circles but I don’t care.