Well, the whole OS does not load into RAM as far as I know.
Anyhow, according to this, maximum USB 2.0 bandwidth is 60MB/s but no generic flash drive is close to that yet.
So, the answer is no, you will see no difference between USB 2.0 and 3.0 for flash drives.
EDIT
As babca said, 60MB/s is theoretical speed of USB 2.0. In practice, it is around 30MB/s according to this. I have done some research and found that there are actually some flash drives that go beyond USB 2.0 speed. (did not know because none of them are sold in my country, and also all are too expensive yet)
Focusing back on your question, the answer is still no in my opinion. Because I don't think you will ever use the 32MB/s transfer rate for home use. (you should actually define that home use you said there).
I assume the maximum transfer rate you will need is watching a Blu-Ray film, unless you have a super duper over-240Mbit/sec internet connection bandwidth. Blu-Ray disc's read mechanism allows 4.5MB/s only, so I assume you will be able to watch quite fine.
Conclusion:
You will see little to no benefit from USB 3.0 transfer rate for home use. Adding the over-price of USB 3.0 flash drives to the equation concludes that sticking to USB 2.0 is fine.
Are you using it strictly for boot, or will there be any OS files on it? – Ignacio Vazquez-Abrams – 2012-08-14T21:31:43.257
I'm booting all the way from it, including loading the OS. So perhaps not strictly speaking just booting. But in the most common use of the word, I'm "booting" from it. – iconoclast – 2012-08-15T14:24:42.087