Are variables always global with NXT?
Yes, global.

5 variables may be 4 more than required. I think one is enough.

Set intSensor = 0
Loop until intSensor &gt; 0
    If leftButton then intSensor = 1
    If rightButton then intSensor = 2    
    If enterButton then intSensor = 3
    If bumped1 then intSensor = 4
    If soundVal &gt; 50 then intSensor = 5
End Loop
If intSensor = 1 then moveForward(135)
. . .