Under USC Title 17 Section 117(a)(1) (IIRC) it is established that copyright is not infringed by installing and using software you purchased, even though installation and use may create a few personal copies as a matter of course. Ergo, you buy box with discs at store, you have the affirmative right to install and use whatever's on those discs; no additional permission from the copyright holder required, since you now legally own a copy.

Therefore you're not getting any additional consideration with (most) EULAs -- they attempt to impose a whole lot of extra conditions beyond those that copyright law provides for, and in return they would give you nothing. (Things like the GPL are an exception -- these actually permit you to do things like redistribute the software, subject to certain conditions. In other words you can do something normally forbidden by copyright law, if you adhere to certain conditions. And you can just plain use it personally as you see fit regardless.)

Q: What is a legal document that purports to take away some of the rights and privileges you already have with respect to something you purchased in a separate transaction earlier in time, in return for absolutely nothing?
A: Null and void, under the contract laws in most states! Especially since there's also no meeting of the minds, no signature, no documentation, no evidence that anything was "agreed" to by anyone...