Im a little late to this topic, but I have to say this:
DONT USE USPS!!!!
Seriously, I know USPS is cheaper and thus people will want to use it more, but when you send something USPS it is effectively lost until it is delivered. Seriously, good luck trying to find something that is going USPS. The post office can only tell you where it was accepted at, then its on you to call the local post office where it was accepted and see if they can tell you when it went out. Even then they may not be able to tell you much.
FedEx & UPS give tracking numers for a reason, so you know where the hell your stuff is at. Each hub the item gets to, it gets entered into the system, problems and all. You know it went to "middle of nowhere, USA" on 02/18/06, entered into the system, and shipped out at 9:45pm. FedEx & UPS can also tell you where the truck will hit next, which hub, so you have some idea of how close or far your item is.
My first EE deal was my NIB DSA Stg 58 for a PSL + accessories, I took no chances, I overnighted the Stg58 and put full insurance on it. Yeah it was expensive, around 85 bucks, but that 85 bought me a peace of mind, I knew where the package was and the estimated delivery time (cant even get that with USPS).
So far everything that has been sent to me with USPS has arrived, so Im not saying they suck as far as getting the item to you, just that they suck with telling you where the hell its at and when the hell it'll get there, and if it is lost they probably wont be able to find it because they themselves do not enter it into any system.
END RANT, sorry, just had to get that off my chest.