Everyone has a personal preference, but between 50-60 grams is standard these days. It used to be a lot lighter on average. I like bags over 60 grams, but that tends to shorten the life of a bag a bit.
yeah i agree with previous posts, it all depends on what you like, i myself like a variety of weights depending on size. I also can deal with lighter bags depending on how they play, but i tend to head towards the heavier side of the spectrum.
Ive starting warming up with an 80g , then play with a bag fronm 55 to 70g, I like the transition because after the 80g , I feel alot faster with the 55. Ive just started doin this, but can already see an improvement.