Not very effecient. I would probably drive the LED with a current, using the transistor's active region, constant current capabilities. Connect the LED directly to the collector. Choose an emmiter resistor by this:
1) Determine base "On" voltage. Subtract .7V for vbe drop
2) Choose emmiter resistor as (Vbase(on) - .7V)/I(LED)
3) Make sure VCC - VLED < Vbase. Use resistive voltage divider as necessary.
4) Might need pulldown resistor on base connection for complete turnoff
5) Make sure ILED x ((VCC-VLED) - VE) < PMAX (.1W) VE is calculated in step 1.
Depends on how your driving the base. Use resistive divider equations and consider the resistance of your driving circuit to insure the "on" voltage is sufficiently high, and the "off" voltage is sufficiently low.
Whats the difference between having resistor +led to collector and emitter to ground VS led to collector resistor across emitter to ground ?