The tbolt has a 32GB card preinstalled which is a $50-100 value.
The tbolt has a 1400mAh battery, the Inspire has a 1230mAh battery.
The tbolt uses the cdma/lte variant of the 45nm cpu (similar to the MyTouch4G, G2, & Desire models) which are faster, have a better gpu, & are more battery efficient. The Inspire uses the gsm vairant of the 65nm cpu(Evo & Incredible). The 65nm processors came out in early 2010 and were installed in new phones through the middle of the year. The 45nm cpu didn't show up until after the middle of 2010.
The tbolt has a better back plate as well. One of the hands on reviews (either on Engadget or one of the Android blogs) said the Inspire has 2 or 3 pieces that unsnap for the battery (on the side) & the sim card (on the bottom). They said the removable doors weren't the easiest to remove or replace. The tbolt has a single removable door that spans from the top of the phone to the kickstand.
The tbolt will make use of Verizons 4G/LTE network for data, while the Inspire's data will run on AT&T's HSPA+ which is more 3G than 4G.
While I wish the tbolt was priced more like current top tier smartphones ($199), I can see why they're charging a premium for it. Between the sd card & the on board memory there will be 40GB of storage on it, which is the maximum it will accept, so you don't have to upgrade it later. Sounds pretty decent to me.