best settings for M4V file

Has anyone experimented with the optimal minimal settings for an M4V (aka MP4) file and use with MEDIA PLAYER?  I am converting some of my movies and TV shows to MP4 and want to make sure what works for the screen size (800x600 is the optimal size?); and what is the video frame rate? 

Already know the audio encoding rate should be around 128 KBPS typically.

 

Forgot to mention, this would be for streaming over WIFI to my apple TV in wifi mode.  The server in the house is also on the WIFI, so would need to consider that.

 

I use handbrake with the built in ATV2 preset.

 

Good point.  Am using MCEBUDDY with my WMC TV recordings, to convert-move files, and the settings can just use the parameters that HANDBRAKE sets.  The folks who developed HANDBRAKE know best what the settinsg should be.