Oh, that's easy. You just browse through the forums and see which one houses your topic the most appropriately. Like, if it's about Pokemon you should automatically look near the top of the forums for the Pokemon General forums. Then try and narrow your topic down. Is it about the Pokemon games? Or the Pokemon show? etc. I'm pretty sure yours would go in the thread marked Pokemon General (at least, I think that's what it's called) because it's not really a game or TV question, it's simply a question about Pokemon in general. Although it could also go in the Other Voting Polls if you add a poll, considering you're asking for the favorite Eeeveelution.
From what I see, though, it has been moved to Pokemon General. So no need to worry. Just make sure that everything is put in the most specific forum you can find for it.
...oh gosh. I'm so used to telling people where to put their stuff on Mibba that I totally didn't even realize I was mini-modding when I said that in your thread. XD Sorry about that. My post got deleted anyway so...yeah. ;p