Dream Team

Have to have a starter so...
Swampert
Pinsir
Lapras
Tropius
Metagross
Garchomp

Garchomp
Metagross
Infernape
Magnezone
Rhyperior
Gyarados

This would be hard for me to choose but

Dragonite
Umbreon
Gyarados
Garchomp
Infernape
Mime Jr

I really like my dragon types which is why I used Garchomp instead of Tyranitar. Also I just like Mime Jr. Because of how funny and cute James' one was in the anime

Just going by favorites...

1. Reshiram
2. Typhlosion
3. Blaziken
4. Sneasel
5. Gallade
6. Garchomp

Swampert
Lucario
Typhlosion
Darkrai
Scrafty
Serperior

Meganium
Sceptile
Houndoom
Heracross
Skarmory
Lugia

Very hard question.

@Blue Dragon; The player you saw using mono Dragon might be a player called dragon Champion Iris (they plays under loads of other names too) who is an Italian player who often plays on Japanese servers and uses a Japanese name. I played them in a minor tournament final a few days ago.

As for my dream team of favorites I'd go with:
Darkrai (The king of sleep and swag)
Maganium (The queen of flower power)
Flaafy (Just cool)
Wigglytuff (Again)
Clefairy (And again)
Haunter (Badass)

Well, i can't put all my favourite pokemon in one dream team, so i'm gonna put more than one dream teams

Tyranitar,Charizard,Feraligatr,Torterra,Alakazam,Salamence

Salamence,Charizard,Blastoise,Torterra,Lucario,Dusknoir

Vulpix
Lapras
Mew
Dragonite
Kangaskhan
Porygon

My favourites. <3

Id probably have to go with my team thats on my sig but with two changes:

My Team
Charizard
Sceptile
Feraligatr
Krookodile
Scizor
Haxorus

This is a pretty easy question for me because it's my team in White and with the exception of Stoutland it was my team in HeartGold-

1. Stoutland
2. Arcanine
3. Dragonite
4. Blastoise
5. Snorlax
6. Mew

I have a reserve team too made up of Pokemon I like a lot but just not enough for any of them to break into the first 6 -

1. Alakazam
2. Ninetales
3. Psyduck (with an Everstone)
4. Empoleon
5. Hydreigon
6. Espeon

My team

1. Arcanine
2. Flygon
3. Torterra
4. Braviary
5. Kingler (Shiny)
6. Lucario

Typhlosion, Weavile, Gyarados, Tyranitar, Raichu, Slaking

Difficult question.

Hydreigon
Haxorus
Darkrai
Thundurus-T
Volcarona
Reuniclus

Doesn't seem to be a team with much synergy, but they're my favorites.