In summer it gets pretty hot thru most of India, so get clothes to see you thru the hot and sometimes humid weather.
Floaters/ sandals etc would work well for footwear-in summer.
In winter, it gets pretty cold (goes down to about 2 degrees cel) during part of december, january and the first half of Feb. So carry suitable clothing.
In the south however, most parts dont see much of a winter...
Photo Equipment: You should get pretty much all you would need here... including memory cards for your digital cameras. Though if you`re visiting the non metro-smaller towns, digital camera users would probably be advised to have enough memory cards/space before setting out. Though nowadays, most towns, unless you`re really headed to the back-of-beyond, would cater to your digital needs
Miscellaneous: India uses a 220 volts/ 50Hz electric supply.
Unless your electrical devices are dual voltage (110-220), you may need to get a voltage converter. Though these are easily available at most neighbourhood electric goods shops.