This would seem to be the best price for a standalone 4GB 360 console at the moment.
You need to go to http://www.walkers.co.uk
to register for their 'Rainy Day' promotion, then collect a 10% Zavvi discount voucher with your free points.
Using the voucher will bring the price of the console down from £134.95 to £121.46
Go through Quidco for a couple of pounds cashback, making the effective price under £120