Well actually all that you need to worry about is the QUALITY of the PSU.
If the case comes with some cheap crappy PSU, it may take a dump, and damage the other components also, like your processor etc
When your spending $2000 on a system, it makes real good sense to buy a good PSU too, so that you can enjoy your system's performance without the fear of the PSU shorting out one fine day
I don't have much knowledge on PSU's , but brands like Corsair, Antec etc should be better than no-name PSU's anyday. Just google, "Tomshardware Good PSU" and that shud help u decide:)
Specifically, see this link, http://www.tomshardware.com/reviews/Components,1/Power-Supplies,6/