Nozzle temps and bed temps depend on the filament you are using, your printer, and even the type of part you are thinking.
I normally set the nozzle temp in the middle or higher end of the manufactures recommended temp. Higher temps are not always better.
Your bed temp should also follow the manufactures recommendations to start with. Different plastics respond to bed temp differently, don't assume that a higher bed temp will reduce warping.
Slumping is another problem to consider. Too high of a bed temp can soften the part near the bed and cause it to slump. This can be a big issue with PLA.