Hey I'm about to pull the trigger on a 27" iMac with a 1tB fusion. Now I really wanted an all internal SSD but I'm gonna have to settle cos the dollars are too intense. SO I'm going with the Fusion drive plus an external SSD. What I wanna know is, is the LaCie 256Gb thunderbolt external drive (priced at £250=$400) a good price for what you get or is it a rip off? I ask because its conveniently on the iMac order page as an add on so I wanted to go with it but suddenly suspected it might be a rip off....any thoughts?