How to force 'top' to show human readable values for %MEM RES and VIRT
If you press h, the help screen contains, among other things:
Z,B,E,e Global: 'Z' colors; 'B' bold; 'E'/'e' summary/task memory scale
Pressing e cycles through mega, giga, tera and peta-sized figures (and the default suffixless kilobyte) values.
After selecting the size, press W to have top save your preferences to ~/.toprc. Now it should start with the preferred size.