The new Silver Xbox 360 controller will be available in the UK from 4th March, priced at £44.99.

According to Gamerzines, that price includes a Play & Charge add-on.

The new wireless controller, revealed last August, offers a "transformative" D-pad for more accurate control that rotates into either a standard 'plus' shape or a disc depending on your preference. It also tweaks the thumbstick, giving it a new concave top, and adds a grey tone finish to the A/B/X/Y buttons.
The new controller is already out in the US, with an RRP of $64.99, which converts to about £41.

The standard wireless controller currently sells for around £30, depending on where you shop.

Source: Silver 360 controller dated, priced Xbox 360 News - Page 1 | Eurogamer.net

I was considering picking this up but then decided not to wait and then bought myself an arcade stick.
Still a very good controller for fighting game fans.