Whitefield, Outer Ring Road & Sarjapur are a great place to invest... Number of factors in favour include good social infrastructure (hospitals, great schools, large malls, supermarkets.. everything you need is within reach). The IT belt of Marthahalli-Sarjapur is providing the impetus for further growth in these areas.
If you have a longer horizon (say 10 years), then North Bangalore is a good option. Current issue in the North being water availability.
Properties in North Bangalore, near to Bangalore International Airport, Outer ring road, and Whitefield are the happening parts of the city having numerous malls and other establishments. The rates in these parts are expected to appreciate furthermore in 2-3 years time.