Turbo Boss, you led me astray with your "200mw" statement. Now you say it's 200 ohms. If you expect good advice, you must be careful to answer questions accurately. A 200 ohm load will draw 60ma, so we should probably have at least 3ma of base drive (conventional wisdom would require 6ma, but we'll fudge a little). So, for 3v drive, we'll have about 2.3v across the resistor (the base-emitter voltage is about 0.7v). The base resistor will then need to be 2.3/3ma=767 ohms. We can use 750 ohms, but now we will get about 15ma of base drive with a 12v input. This may be too much drive for a 2N3904, but worse, it's probably too much current to draw from your 12v driver. If not, use 750 ohms.
Below is a circuit which will provide 3ma of base drive for any input from 3v to 12v. It is complex, but it only draws about 3.3ma from the driver over the input range.
Nettron, your zener idea won't work. The base voltage will never get above around 1v, because the base-emitter is a diode to ground. You must be thinking of a MOSFET. In fact, a MOSFET might be the best solution if there is one available with low on resistance at 3v base drive.
I've been assuming Turbo Boss wants to use the 2N3904.