Most if not all of the cases of these supposed "bricked" phones are not even close to being bricked. Generally it's a matter of: 1. not following directions or 2. downloading a corrupt or incorrect file. Also, things like using an incorrect kernel for overclocking can keep your phone from booting up. These are all very easy issues to fix. People new to rooting their phone consider a minor mess up as being "bricked" but that's just not the case.
I do understand your worry with the money issue of having to buy a new phone if your phone did actually become unusable. If you do not feel comfortable I would never suggest rooting the phone. This is where these apps such as rom manager will make the process very simple, but take some of the learning curve out of the process and can actually hinder the user fixing issues on their own.
Honestly, I do not see Froyo being officially released until at least early August. If the X was being released with Froyo then things would come about faster but since X has version 2.1 this will cause delay. I do prefer having an official release and then having a rom built off that over a leak version .... but right now I am fairly happy with the leaked version and have to believe it's going to basically be the release version.
