I continue to be intrigued by the differences between British/American English and Indian English.
I also wonder regularly if some of the grammatical problems I see in submissions written by South Asian writers are merely examples of Indian English. Some day, I should sit down and read more published South Asian writing to try and get a better feel for Indian English.
(I've read a few novels by South Asian authors, but not enough for a representative sample yet.)
See also: the online Dictionary of Indian English; 108 varieties of Indian English; a 2004 paper from Language in India on linguistic majority-minority relations in India; and a page of audio pronunciations of English words in New Delhi.
That last, btw, is from the extremely useful-looking Accents of English from around the world website. I hope to spend some time poking around there and listening to pronunciations in the future.