Gengar, it's my favourite ghost pokemon.

Spiritomb or Sableye?

Spiritomb, its an awesome version of sableye.

Jynx or Piloswine?

Frankly I've never been a fan of either...but I'll say Piloswine - two of favourite types in one and it looks like a mop

Baltoy or Barboach?

Barboach, Baltoy just sucks. It's evolution does to.

Physchic or Dark?

For this game definately Psychic - too many things use dark for attack rather than special...but Diamond wise, I'd probably go with dark

Weather ball or Tri Attack?

Tri Attack, i hate Casform, I love Porygon and it's evolutions.

Plusle or Minun?

Minun it's soo much sweeter and I prefer the blue over the red

Marshtomp or Dewgong?

Marshtomp, when it evolves it can do major damage.

Golem or Onix?

Onix, he's awesome especially the episode where one was made of crystal.

Yanma or Ledyba?

~In the darkness shining far beyond the starlight~

I saw that episode. It was really neat when Mateo had his charmeleon use Flamethrower on the crystal onix and then was about to catch it but decided not to and just watched as the crystals cooled and sparkled.

Anyway, I pick Yanma, because it's a cool pokemon and it's evolution looks a lot better than Ledyba's does.

Milotic or Piloswine?

I'll have to say Milotic, Piloswine isn't good competitive.

Magmortar or Charizard?

Magmortar, Charizard looks cool but it's not as cool as magmortar which just looks plain awesome.

Magmortar or Electivire?

Electivire, both very great pokemon but electivire suits my competitive team better.

Jumpluff or Tropius?

Jumpluff for sure.

Minun or Plusle?

~In the darkness shining far beyond the starlight~

Oh well again I'll say Minun because it's sweeter and I prefer blue over red

Venemoth or Golduck?