I decided a complete cleanup was needed. So let's do this!
In here you'll find important threads.
Of course, no thread would be complete without mentioning the holy grail of Pokémon Video Games, the Simple Question thread! Post questions there, and we'll do our best to help answer them.
1) The "Is My Pokémon Hacked?" Thread - Check the validity of the Pokémon you traded for!
2) 4th Gen Trainer's Travelog - Keep up to date with your friend's adventures!
3) Ruby and Sapphire Remake Discussions - Speculate and discuss the potential remakes of the unforgettable Hoenn adventures.
4) Nuzlocke! - Keep up to date with your friends' Nuzlocke challenges!
5) http://bmgf.bulbagarden.net/f323/clever-pok%C3%A9mon-nicknames-24056/ - Share your clever Pokémon nicknames here!
6) Your first shiny. How? when? where? - Talk about your first experience with a Shiny Pokémon.
7) The Shiny Encounters Thread - The new general Shiny Pokémon thread.
8) How to Make Dream Pals 2 - How to make friends in the Dream World quickly and easily!
9) http://bmgf.bulbagarden.net/f323/current-upcoming-pok%C3%A9mon-events-75465/ - Stay up-to-date with free Pokémon giveaways!
Also, here are a few of the most popular "what's your favorite *insert thing here*" threads.
1) Favourite Game
2) Favourite Pokémon
3) Favourite Region
4) Favourite In-Game Music
5) Favourite Female Player Character
6) Favourite Male Player Character
7) Favourite Battle Frontier Facility
8) Favourite Pokemon Type
9) Favourite Signature Move
10) Favourite (and least Favourite) Pokémon cries
Feel free to post links to new threads you think should be here!