I really like the CRT Pi Shader, however I am running a 720p TV and the presets don't look quite right (I believe they are set up for 1080p) so I have a tweakes version of the shader I use for 8-bit and 16-bit.
as for N64, I tend to use the Hi Res emulator options in Retropie. Looks better than my actual N64 plugged into the TV ad nearly on Par with the ports in Rare Replay on Xbox one.
Video Smoothing can be nice, but it's just too soft for me these day (hence the shader).