If I install Launcher Pro at some point can you uninstall it and go back to touch wiz????
Yeah, you should, but you may have to set everything up again. I have a DINC and owned the X for a while. Moto Blur on the X sucked compared to Sense on the HTC. You will find that opinion common. Sense seems to be the best regarded skin installed by a manufacturer (from my reading on reviews and forums).
Its much more polished, and the widgets on the X were really poor. Some folks hate all the skins and like launcher pro. I tried LP on the X because Blur was so bad. It did help for sure.
That said, with 7 home screens on both,TW and LP (you can customize how many home screens in LP) they are pretty similar. Stock Android only offers 3 home screens. Change your wall paper to what suits you (I like plain dark color un-animated, to free up resources and extend battery life) and they should be more similar than different.
The paid ver of LP comes with some nice widgets from what I read. I Getting the fascinate tomorrow. I'll run TW to see how it differs from Sense (on HTC phones). Probably try to find the widgets I like in the Market and run them on TW for a while.
Hope that helps. Since this is your first android,use TW for a while so you can understand the differences on other skins. Once you get a feel for android (very intuitive) and understand TW then go to a store and play with a DINC and an X. The difference will be readily apparent and you can figure out if TW is what you want to stay with.