Still, 30 min is damn good. My UPSessss are only 350va, fortunately I haven't had to find out first hand yet, but I'd bet I get less than 10 min, maybe less with the 17" monitor.
I think you missed the thread about my 17" going to warranty, then borrowing a 14" from a friend (that went south) and borrowing yet another 14" from my sister0s bf (which is the one i'm using right now)