If you do not mind the recommendations of an unsmart one, read further...
> Can anyone recommend one or two good, basic histories of India,
> particularly
> modern times? Also, are there any notable left authors from there
> (besides
> Roy) I should check out? I know nothing about india and i want to
> learn.
Unfortunately, I do not have anything recent that I can recommend -- do not recall what Romila Thapar (??) covers in her book, nor do I recall the details of Guha's "India After Gandhi". Guha can be a stuffy character at times and his more than fleeting interest in that scourge of a sport cricket is irritating, but I have tended to like his writing, overall; so I recommend it.
But here are some more general suggestions: Nehru's Discovery of India is as good a start as any that I can think of. If you want the esoteric stuff then Radakrishnan's two or three volume Indian Philosophy should solve any insomnia issues. Everyone has to get past Wolpert, I think, so you might as well give it a go (India -- Stanley Wolpert).
Regarding authors: I do not know about left authors given the different interpretations of "left" (to me, given my Indian roots, "left"ism is a consequence of "humanism", and in that sense many of the authors mentioned are "left authors" -- YMMV). I am not a big admirer of Roy, though I have softened my views on her non-fictional output (her fiction is still a bit too "ethnic" for my taste). Rushdie and Naipaul are eminently avoidable. Vikram Seth is worth a glance. As also R.K.Narayan, my own favourite Indian author. Tagore's writing and poetry are definitely required reading. Then there are the others: Shashi Tharoor, Rohinton Mistry, Jhumpa Lahiri (not an Indian), Ruth Jhabvala, Kipling ;-), etc.
Note that India is many different places and you hear more of some than others (sort of like what passes for "Indian" food in restaurants outside India, including the UK, "naked chef" notwithstanding). You will have a tough time finding a detailed enough history, for example, of one of the greatest revolutions (IMHO) in India (dare I say, the world?), the Dravidian movement in my home state of Tamil Nadu.
--ravi