There's a good offer for the OCZ Agility 3 240gb for £150.
I'm thinking of getting two of these and putting it into a raid0 array, to replace my single 256gb Samsung 830 Series.
Do you think that would be a beneficial thing to do?
^no,OCZ has highest failure rates(you will also loose TRIM support) and samsung is one of the most reliable SSD maker.
265gb is quite big for a ssd.better upgrade any other component of your pc.list your current specs please.