According to this article, India's military leaders now consider China their biggest threat.
China is modernizing its military at a rapid rate, including upgrades and exercises aimed at moving Chinese forces thousands of kilometers in a short period of time. China naval activity in the Indian Ocean has been on the increase.
India's headline-grabbing adversarial relationship with Pakistan, on the other hand, appears to be on the wane. Pakistan is thought to be much less of a threat to India, a realization brought about in part by the first-ever publishing of Pakistan's military budget, which produced a number smaller than expected.
Will China be satisfied with the Himalayans as a buffer? History tells us that China is not very expansionistic, particularly compared to Russia, though it does like friendly (or puppet) buffer states.