Throwing my response into the mix:http://www.avsforum.com/avs-vb/showt...8#post15831688
FWIW, my advice is to try a DIY option first and if you're not satisfied then proceed to more elaborate solutions, the most you'll be out is roughly $5 so I think its worth your time (the bulb is typically $5 and I don't believe you can return it, the ballast you can return)
I've had this for a few months now and my wife and I are both happy with the results. I find it most useful for being able to watch movies without any other lights on to wash away the picture.
Best of luck.
Edit: There is no such thing as the 'best' light for any condition. As mentioned by another member, the circumstances of your set-up affects many factors that should be considered (depending how deep you want to get into the subject)
such as wall colour. You didn't mention in your OP if your set has been calibrated (either by a pro or a DIY, just make sure you educate yourself on the subject)
but that would be my #1 advice in improving your PQ, then follow the whole bias lighting subject. As for needing 1 or 2 lights, again, it all depends on the set-up (size of room, seating position, etc). I only have one behind my set (58") but I wouldn't mind a little more light output out of it (my pictures in the referenced post are a little deceiving, its not that dark in my HT) but I would opt for a bigger tube (T12) before adding another one (currently a T8). At the end of the day, I'm in no rush as I'm plenty satisfied with it as is (it has accomplished its job for me).