Wirelessly posted (BlackBerry8700/4.1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/125)
Unless using Amex 2-4-1, I have always learnt to book 2 one-ways not a return to give the required flexibility.
Also if you have a trip to somewhere is Europe, you can get USA-LHR-XXX with a long stopover in LHR for no extra miles.