As a US citizen living in China I'm actually a little puzzled by the posters here; I have zero interest in acquiring a local charge or credit account as I know it will only be temporary until I return to the states in 5 to 10 years.
Nothing you do credit wise in the local country will count for "credit" in your home country, so you're just setting yourself up to have to re-prove yourself when you move home if you don't stick with your home credit cards.
Accordingly, I do have a cash / debit account but only use it when absolutely necessary.
Also, if the above doesn't sway you and you're convinced you need a US credit card, there's an easy solution:
Grab $50,000 or so from your home investment accounts, deposit it with a US branch of UBS in a RMA account (or find an equivalent at another bank), and get a set of no fee, non-securitized (in theory they're securitized by your investment balance, but if you default they can't go after your UBS deposits) cards with a limit equal to your deposit with UBS.
Bingo, "real" cards with high limits issued by US banks, with a reward point feature, and if you pay the fee (~$500) you basically get AMEX platinum benefits too.