UPDATE: The only backpackers bar in Urumqi
If you have a China guidebook, they are all seriously out of date for the city of Urumqi. I.e. John's Cafe has closed down, a year or two ago, and The Holiday Inn has been renamed.
As a result there is only one backpackers / foreigners hang out in town: "C D Bar". However this has newly opened and so isn't in any guide book yet.
This is near the southern area of the city centre: Basement floor of a large building on the corner of a large junction: CD bar, Xiao Ximen, Min zhu Lu 83-1.
If I happen to be there, say hello!