I use my Kindle DX (best for PDFs) outside the US all the time. The new DX will also have international access (which can be disbaled). Plug it into a USB, and drag and drop your files.
My eventual conclusion was that I needed an ebook with a bigger screen. After waiting and waiting for an apple tablet announcement I went with a kindle dx and it has been great. It does not hit all of the items in your requirements list (I keep the wireless off to conserve battery, the keyboard is almost never used except to jump to specific pages, and it's support of annotation is "weak" at best) but it is probably the best option out there for my needs.
My advice would be to start by deciding what screen size you need and letting all other requirements and feature comparisons flow from that decision.