Less and less so every day. We now disregard the gox price at bitcoin.co.th
I beg to differ, Gox's price is regarded as THE correct price. The problem is that new comers are unaware of any other price indicators and fall victim to exchanges such as Gox.
I beg to differ -- When I was a newbie I disregarded the Gox price and only went by local exchange price. On short timescales I got burned quite badly doing that. Later I learned from my mistakes and started to pay more attention to Gox.
Right now though, things do seem to be changing -- but it's not clear yet. Bears will happily tell you to follow Bitstamp, because conveniently it is lower right now. I believe this is due to Bitfinex tying their shorts against the Bitstamp price. BTC-E has always been lower, and BTC-China has always been a follower of Gox price -- waiting for clarity on direction now.
I think right now for general purposes, the most useful would be to follow a basket of Gox, Bitstamp, BTC-E and and BTC China, with Gox making up about 80 - 85% of the basket and the others accounting for the remainder.
And as usual, trend over a few days is more important than any one price on a particular exchange at a point in time.