newbie piping questions - what size return - what size overflow?

[Milad]

well I dont know which pump to get yet. I wanted a good quality pump with very little noise.
i was looking at either:
http://www.jlaquatics.com/product/tz...+1073.040.html

or

http://www.marineandreef.com/4_MDQX_...p/rlg82507.htm

suggestion on the pump?

thats why my other thread was started so I could figure out which pump to get!