Topic: Who to catch in HG/SS with a Master Ball?

well, on the pokewalker yes... but im not sure if a pokewaker-caught pokemon can be counted as a pokemon caught in HGSS

Bah, don't even use it. The Master Ball is like The Mark of the Cheaters. Trade it to a friend for a really rare Pokemon.

Save it for shinys, or the runners. Otherwise use

I started a while back only catching Pokémon with standard pokéballs. Occassionally I'll use Ultraballs on Pokémon that stop gameplay (3 pixies in DPPt mainly), but I rarely if ever use masterballs anymore.
Looks much better if you catch Pokémon in any ball other than a masterball.

The best ball is the luxury ball. Nothing looks cooler than having a legendary caught by one of those.
It shows that you have skill, patience, and great style.

EDIT: (minor change)
EDIT: The only problem is that they are only available on Sundays as the second prize for the Goldenrod department store lottery.

But they're so expensive! Not to mention the crazy tax.

I like to use every other kind of Pokéballs but not Masterball (as I said already that I don't like those) and it also shows up when I throw my Pokémon to battle. I use usually Poké, Great and Ultra Balls but if they won't work I might use some others like Net Ball (I like these Balls) or Dusk Balls. Oh, there's one Ball type that I hate with Master Ball and it's... Premier Ball! I can't get anything to those things, not even those low leveled Rattatas and Pidgeys then comes a Pokémon that I can't get and after 10-20 balls I throw Premier Ball and then it actually works... (I dunno why it happens so often...)
And it isn't that hard to get Legendary Pokémon to normal balls. I've caught full energy Azelf with normal Pokéball (after throwing one Ultra Ball first) and Articuno with Net Ball after few random balls. (Almost got Zapdos with Net Ball too.)
It took a while trying to catch Mewtwo and best ball to work on that one was normal Pokéball (Shoot! It was so close too happened so many times) but then I got it with Ultra Ball.

A lot of text that didn't answer to your question but I have always fun to write about my happenings in game

@Late
Here, this should help you understand.(keep in mind that wherever " * " is seen, multiplication is used) http://www.serebii.net/games/capture.shtml
If you don't want to go through the trouble of messing with the formula, then you can just scroll down to where the Pokeballs are and check what number they multiply the chance of capture by.

Magikarp

_{seriously, splash is just plain epic}

"And God said 'Let the waters abound with an abundance of great creatures' and then there was Magikarp."- Genesis1:20a(directors cut)

That's what you do with it.