In truth, I doubt I'll replace the sensor. Other than these photos of fireworks I can literally count on one hand the number of times that orbs have appeared in my photos (not counting test photos where I was TRYING to create orbs). I mostly use my X10 for candid portraits and some product photography in a light tent and orbs haven't been the problem for me. I am certain that the orbs would be a bigger issue for me if I used the X10 on a regular basis for evening landscapes with street lights in the frame or photos on/near water with the sun reflecting off the water ... but the type of candids and product shots I do with the X10 don't usually produce orbs.
I might send my X10 in for sensor replacement if I didn't have other cameras, but I have four m4/3 cameras and three DSLRs so if I am shooting something that is likely to produce orbs I can bring another camera instead of the X10. I only used the X10 this time because I knew it would likely produce orbs and I wanted to see how it would look.