I started using XE.com relatively recently, and found couldn't be happier with it.
I was initially concerned about the verification of identity process, but it was much easier than I'd read about previously - I was able to do it just by providing my credit card number (which is not charged, it's just for verification). A day or two later I got their email saying my account was activated. No need to scan/send docs etc.
The last couple of trades I've sent money on a Monday morning. The confirmation from XE that they'd initiated the payment came later that day, and the money was in my US bank account by the Wednesday afternoon, thanks to Faster Payments (UK end) and EFT (US). No fees charged by either my UK bank or my US bank.
(I used to just use Natwest's wire service.. for which they charged £20 (£27 for an 'urgent' transfer

), and also I'd be hit by a $12 fee from my US bank for receiving the wire as well. I won't be doing that again any time soon.)