Where is meditite in Pokemon Emerald?
You can not get Meditite in Emerald. You must trade from Ruby or Sapphire.
Meditite aren't found in the wild on Emerald. To get one, you have to trade with Ruby, Sapphire, Colosseum or XD. In Ruby and Sapphire, they are found on the outside of Mount Pyre and in the first basement of Victory Road. In Colosseum, you can Snag one from Rider Twan in Pyrite Cave and in XD, you must trade with Duking (he asks for a Trapinch).
If you mean item, it's a Nugget. The most valuable game... it depends. Emerald is probably the best, but it doesn't have some Pokemon. Ruby and Emerald are nearly identical (Ruby doesn't have the Battle Frontier and Emerald doesn't have Zangoose, Roselia, Meditite/chan or Suskit/Masquerian), so if you have Emerald I'd get Sapphire. I would get Emerald, though.