For the best chlorine reduction, I would recommend the granular activated carbon technology because of the great contact time it offers. It does slow down the flow rate, so you probably need a bigger filter, such as this one.
http://www.waterfilters.net/culligan/wholehouse/replacement_filters/GAC-20BB.htm
You can use this system for all the water coming through your house.
If you want the best arsenic reduction, you should get an arsenic system.
http://www.waterfilters.net/Arsenic-Treatment-Products_c_129.html
This system will reduce the pressure, so it is used just for undersink filtration.
Thank you,
WaterFilters.NET