I've been debating between the GT30 and ST30 for the last few weeks and I can't decide, and this latest deal doesn't make it any easier on me as the glasses bundle is like $250 alone - good thing that the bundle comes with either the GT30 or the ST30 lines.
Initially I was leaning toward the GT30 because I typically buy the 2nd level tier (as opposed to the 1st tier VT30 class). To me, the GT30 has a slightly better looking bezel which is also smaller-sized than the ST30 - I think there's about a ~1.5 inch difference between the width of the two TVs depending on size. The GT30 also has an extra HDMI input, is "slimmer" than the ST30, and it also has "THX" mode which some people debate the usefulness of compared to manually configuring all the settings correctly on the ST30 - which there are many threads over at AVS to help one do it correctly. I think I remember reading some posts over at AVS saying that the ST and GT use exactly the same panels, so outside of THX and the extra HDMI, there's not much difference.
As of yesterday's prices, there was a $55 price difference between the 50GT and the 50ST, but a nearly $190 difference between the 55GT and the 55ST (which would make it more worth it to go with the ST). I was also thinking that with yesterday's prices you could pay an extra $50 and get the 60ST instead of the 55GT...