That really depends on you. The anime gets to the important things of the series while the manga usually has a lot more to it, like excluded characters and events (though much more time consuming)

Watching in anime is a lot more dramatic than the manga ( mah opinion)

I'd watch the anime first coz the manga usually follows on from the anime!

I always watch the anime first and if I liked it I read the manga too

Either one really.

It depends on the series.

The manga is more thorough.

If you read the manga first, you'll probably be disappointed with the anime, plus usually the anime is easier to follow since its animated, but the good thing is, with most anime they have a much longer manga so once you've completed the anime, a longer manga is waiting for you ^^

Actually it depends on the series and I think either would be fine to do first.

The way I see it, it's like reading the book(s) before you watch the movie. It's more in depth and you'll see everything that the movie should have but end up taking away. (mostly for time)

Even though I always prefer the anime, reading the manga first seem right.