Why do Indian film makers dub the entire movie after filming rather than just using the sound on location? What is the benefits of dubbing, and essentially doing things twice? Isnt the method in Hollywood type movies location sound? And since Bollywood wants to be like Hollywood so much, shouldnt they adopt this method also?

It is easier to shoot a film without worrying whether a boom mike will be hanging in the shot. The recordists on set have to contend with road noise, airplanes flying overhead, wind, etc. The vast majority of Hong Kong films are dubbed because there is so much noise. Dubbing is probably cheaper than location sound. Many actors and actresses in the various Indian cinema industries are from other parts of the country and are often dubbed over by someone who knows the language better.

Hollywood is usually a mix of location and dubbing (known as ADR in H'wood lingo), though I'm sure a good percentage of most films are shot with location sound. Why more filmmakers don't embrace location shooting, I don't know. Dubbing is often done months after shooting and the actors are not in the mode of the film by then, so the performances may suffer.
I think Aamir Khan will push for location sound on his next films, what with the good results on "Dil Chahta Hai" and "Lagaan" (both by soundman Nakul Kamte).

since we're on the topic of dubbing, how many of you are pissed at the quality of it like i am? in hollywood films it's hard to tell if the film is dubbed because the actors match the movement of their lips so well; but in hindi films it seems as if they don't care if they match the mouth at all. i know if i was a director or producer of a film, i'd make sure the dubbing is done perfectly before the film gets released. i hate seeing actors moving their mouths and sound coming out a second later; it spoils the realism. why don't more directors care?

Exactly theon...I can't stand it when the dialogue doesn't match lip movements. There also other things missing in dubbed sound - realistic sounds of thumps, hits, shuffles and general ambient sounds. Explains the "dhishum dhishum" phenomenon in Hindi films:) At least these days, people like H. Sridhar try their best to do a good Foley job. But it just isn't the same. Even in Company (which is dubbed - though the credits state a location sound recordist), the dialogue recording is noticeably fake. For example the voices have too much "body" and clarity even as the people are walking down the Bombay "basti"s. There is also no effect of the characters' distance from the camera. Though it should be said the film has pretty good sound effects recording.

BTW, for some really badly dubbed films, watch anything by J.P. Dutta, especially Border. Of course there are the obvious people like David Dhawan, Indra Kumar, Mehul Kumar and gang...I really hope these people are on their way out.

Hollywood films use location sound almost throughout the film. The bits with problems in the location sound are then very carefully ADRed in post. They hardly ever do ridiculous things like using another person's voice for another actor. Its a cheap trick. The last Hollywood film I remember being ADRed all the way was a film called "Tank Girl".

Also, these days a lot of Hong Kong films use location sound. They only dub when they release the films in Mandarin in non-Cantonese speaking countries.

DragonR2 has said all the reasons why the Indian industry hasn't embraces location sound wholeheartedly yet. Imagine all the south Indian films with non-south Indian language speaking actresses - Simran, Isha Gopikkar, Manisha Koirala, Urmila, Priyanka Chopra, Yukta Mookhey, Riya Sen, Nandita Das, Tabu, Sonali Bendre, Kajol, Jyotika, Nagma, Khushboo, Devayani, Mumtaj,
Radhika Chowdary, Rani Mukherjee - the list is endless. The South (especially Tamil) film industry will come to a standstill with the use of location sound - with these actresses who no doubt look good and act ok, but are (or at least were) unable to speak the language!