I have this one already, otherwise I would buy it!
This is probably my favourite kit I've got in a while, its a challenging build while giving a fantastic end model. This can easily accept the new Power Functions motors, and I have seen them modified to be full R/C control!
There are also various other LEGO offers on TESCO's website, but this is the best deal I have found so far!
Around £40 elsewhere for this kit, chepaest from quick scan is £34.07 from Amazon.
Blurb From Tesco:
This 286-piece LEGO set lets you build a working excavator, complete with a rotating upper body using hydraulic power to lower and raise the articulated arm. It also has two controls for the excavator arm and bucket. It comes with step-by-step instructions.