I'd take any MP's NOT seperated into Gold, Silver, Bronze and Dark ages.... Just say Series 1, 2, 3, 4, 5.

Anything NOT combiner or Jetfire/Omega/City sized up to series 4 for me. 5 is where the cartoon nostalgia wears off (Seeing them in action with personalities) so anything Series 4 onwards is just a toy.

If they really wanted to push into 5, I'd take the Masterforce characters, but not the entire range. MP is a Japanese line anyway. Victory/Zone similar, but skip the Micromasters.