Just last week I upgraded to a Droid X over an original MotoDroid. I debated it for a while, due to the fact that the X has been out for 6 or 7 months at this point, plus the locked bootloader -- I loved being able to load all sorts of new roms on my MotoDroid.
That being said, I'm a huge fan of the Droid X. I was considering the Thunderbolt, but after a bit of research I began to realize that the Thunderbolt is using year-old tech that has had a slight upgrade. (RAM, and the CPU was *slightly* upgraded; it's really just the same thing as the EVO with some relatively superficial improvements.)
Then there's the issue that, overall, Motorola makes handsets that are of a far superior build quality than HTC.
I'm incredibly disappointed with HTC's offerings. I bought the DX off-contract (on Craigslist for a bit more, but still, $300 for an un-used DX + dock isn't too bad) so that I'll be able to upgrade maybe in another year or so.