Wow- you really saved 50%? That's pretty darn significant.
The last time I had the newer pigtail-style replacement bulbs was in 2003. I think for me, maybe it makes less of a difference because I generally keep my place pretty dark. I am not a fan of brightness- I relax a lot better in dim light. Plus, I think I look better that way too
It was tough to know the difference back in '03, because where I lived (Boston) we had NO insulation, and electric heat. Can you say $600+ electric bill?!?! And that was with the heat off in every room besides the one we were in.
I can tell you, if the light didn't bug me (it doesn't bug you I am guessing) and it would save be $100/mo, I'd do it too! That is a LOT of scratch.