Neteller isn't a bank ...

and neither is Firepay, or for that matter most any third party provider of internet payment services. Since they aren't banks, they are not FDIC insured to protect our funds.
They go belly up and we're screwed if we have funds in there.
So my question is: How much cash do you feel comfortable letting float in these uninsured companies that perform much like banks, but aren't?
Personally I plan on transferring a $1000.00 of it tomorrow. So I guess that means my comfort level is exceeded when I go over a thousand or so. Am I paranoid, or am I actually letting too much build up before transferring?

I guess this answer really just depends on your personal comfort level. I'm comfortable with larger sums in Neteller, but to each his own. With the free transfers in both directions, it's easy to justify pulling the funds into your bank on a regular basis. Of course, when you overdo it, you'll have to endure the week-long delay to re-deposit via free EFT.