1. Fight: Fight types are just always the best in my eyes. They are the original Beat down type. They can devastate an entire battle with only a few moves and lead to some of the great powerhouses we play today. I've been enamored by Fight types since the early Red and Blue days when the king of my team was Primeape.
2. Normal: Normal types can do just about anything. They can cover weaknesses in your team, they can play out a combo like no other type, and they have some of the most powerful and intriguing move sets out of all types. They can fill out just about any kind of position in your team and do it efficiently.
3. Bug: Bug types are some of my favorite types simply because they have an interesting aspect to them. Whenever I play a bug type, it always seems to be filling in for an extreme aspect or mechanic. I don't know if anybody has ever noticed what I'm talking about but Bugs always take everything to the extreme. for instance Ninjask, It's the fastest pokemon (ignoring S-Deo), or Shedinja for that matter, the only pokemon with one health. There are other examples, but that's why I like bug pokemon, they always seem to be taking things to the absolute extreme.
4. Water: Two words: Rain Dance. If it wasn't for Rain Dance, I don't think Water types would be on my number four spot on the list it would probably have to make way for the Number 5. The synergy with Rain Dance and water pokemon in general is so insane, it builds entire teams for me. Although there are a lot of other factors that Water pokemon can fit into, I always ask myself one question when thinking about water pokemon, "How can I abuse this with Rain Dance?" Plus all of the other great abilities that take advantage of Rain Dance make water pokemon my number 4.
5. Dark: Dark Pokemon come in for me at number 5, not because of it's type, coolness, or the pokemon themselves, I love Dark types because of their move collection. Most of the Dark moves all have the same idea in mind: Sabotage. Most of the best dark moves tend to be based on gaining advantage through punishing your opponent. These moves generally work on sabotaging your opponent such as, Taunt, Torment, Snatch, Sucker Punch, Punishment, and Flatter.
Those are my top favorite types. :D