@Mac: I've encountered that worry from a lot of people regarding the 55g, that it will be some sort of drastic difference from the 45g. While the difference is noticeable, IMO it's still roughly the same as typing on something like blues. Like I mentioned earlier, the escape key on a variable is weighted at 55g, so you can at least get some idea of how it feels.
My personal opinion is that the 45g felt almost loose, like the keys weren't really solid. I find myself typing lighter on the 55g than I did on the 45g because of the increased tactility. However, I've been typing professionally for the last 15 years pretty much every day, on fairly crappy RD over membrane boards (up until late 2010), and have never experienced any wrist or finger pain, so if that's something you have to worry about, then your experience with the 55g may be completely different than mine.
I would suggest you buy one and try it out. There's enough demand for them that you can make almost all your money back on it here in the classifieds, and then just get yourself a 45g and not be out much money.