We have used Paypal in the past to send money from the UK to the US and although it was quite speedy, and very easy to do, I must say that the exchange rate wasn't that good when compared to sites such as xe.com when you look deeper into it.
It seems to me that there are just a myriad of options out there and it really depends on what is most suitable to you.
Thinking out loud, she currently banks with Citibank, so I'm thinking about opening a Citibank myself in the UK which, I believe, would allow us free transfers. The alternative is for her to just send the money to my bank account and pay the $45 dollar fee for each transfer. Then once everything has been transferred, have her open a UK bank account when she is here and send the money back to her somewhere down the line.
Argh! This is confusing, I can see why this gives people headaches.