I plan to use web3 server side using NodeJs with geth. For production usage, should I do a full sync or fast sync is enough?
Also, how much space do I need to store the blockchain data for each of these sync types as on today?
You can go for 'fast' sync and it will require about 21gb of space.
Basically 'light' sync is for testing and development purpose.
Fast synchronization is usually OK, you download both blocks and states. However, using full synchronization you only download the blocks, and compute the states yourself. It takes MUCH more time, but you are sure the states are valid. If you don't mind waiting it's always a plus to do it full, but for most cases fast suffices.
Concerning the required size, you can take a look at this chart, which shows it very clearly.
