There are initial low limits but I would have to vote the eCheck as the easiest. Easiest to set up and easiest to deposit. Now, the hold on these depsits (avg 10 days) keep it from being the easiest way to withdraw.
If you want to add some spice to your life, you really should just use Neteller. At multiple points in your relationship with them they will do things that will test your powers of self-control.
Firepay takes way too long to clear.
I have heard only good things about Moneybookers but am not familiar with their product. Neteller has not quite pissed me off enough to cause me to jump ship just yet. Still waiting for the inevitable "much better option" to show up.
Moneybookers costs too much to get the $$ back to your checking account vs. Free from Neteller and their limits are ridiculously low compared to Neteller.