1 4gb memory or 2 2gb

This is for my first gaming pc. I do not plan to do hardcore gaming just do some indi games and terraria. Should i get  just one stick of 4 gb memory card or 2 of 2gb. or should i upgrade for one 8gb or 2 4gb.

get memory in pairs, dual channel bandwidth. either 2x2 or 2x4

You should get 8GB of RAM. Trust me. You'll need it even if you aren't gaming. 

Get 2X4GB and take advantage of dual channel 

These two are correct. Go for more memory, but if you absolutely won't go for 8GB, go for 2x2GB to use the best of the dual channel's bandwidth.

OK thank you everyone!