here was the setup:

5Vdc->R1->2.2vF LED->1.9vF LED->R2->GND
R1=R2
first tried 240 ohm, Great brightness for each, pretty bright with no input
next up 1K, simular results just dimmer
last 4.7K, No real output for off, bright enough to see with input, but not really enough for an indicator in this app.

So my opinion is everybody in this thread is correct in some respect.

I feel like the best solution is to use a 3.3V supply. that way there is NO way to light both, and each can be nice and bright. Now, question for the masses: can we use a voltage divider to get this 3.3 from 5? This seems to me to be the least costly answer. Just 2 resistors and off we go. Hang a resistor inline with the signal pin and life is good. My perticular application will have 6 sets of LED's so if 1 from each set were on at once, could be 120mA.droping 1.7 volts, that would be 1.7*.12=.2W. That part doesn't seem too bad. Of course they could be strobed so there would never be more than 1 on at a time, then it would be 1.7*.02=.034W