First submission. Here it goes.
Tariff: £20 Talker (500 mins, 100 texts) for 18 months + £10 XSeries Gold Subscription (Unlimited Internet access including Slingbox client) + £50 up front.
Here's how to do it. Select the E65 (best XSeries phone on there at a reasonable price) and the £20 Talker Tariff. On the add-ons page, select XSeries Gold + Free Slingbox (careful... there is two Gold options). The 512MB card is thown in automatically.
Next, go through the order procedure up to the payment page (after the personal info screen... make sure you enter your email address correctly). At the payment screen, close your browser window.
30 minutes or so later, you should receive an email entitled 'Reasons to Buy from Three'. This will include the voucher code for the headset.
Go back through the ordering process again and enter the voucher code. Thus, with this package and a Sky account, you can stream your full Sky package to your phone at no extra cost.