People in my guild are from all over Europe. None of them get as low as 30ms latency. A good latency is regarded as 60ms. Acceptable latency is anything below 120ms. Over 120 we start bitching. lol.
Im in London and my latency in Shattrath is usually 126. My fps always hovers around 60. Thats cause I have 2 hard drives, 2gig ram and a decent graphics card. There are guys in the UK who have set their hearthstone to the Allerian Stronghold because their latency and fps in Shattrath is horrible. One bloke who lives about 20 miles from me has fps of less than 10 in Shattrath. His latency goes up to 180 in Shattrath.
We did Gruul's last night and we had a hard time. How healers latency was spiking from 130 to 2k. Something is screwed up on our realm(Alonsus). We wiped twice on a boss we usually take down before the 5th or 6th growth and we regard as free epics. My latency was 160 for most of the fight. It was a problem. I was the 2nd tank, and I often missed the shield block when Gruul targeted me. Used healthstones here for the first time in months.
Did some mining later on, on my alt hunter in the barrens and my latency was 76.
EDIT: before our Gruul's raid, there where about 7 guilds outside. hehe.