We know that accessories for the Mac (in fact all Apple things) are a little spendy but the pricing for the Time Capsule doesn’t make sense.
The Time Capsule is basically an Airport Extreme with a disk drive added (and support for Time Machine. Update: I am told you can do Time Machine to an Extreme as well so even that is not an addition). An Airport Extreme sets you back £139 ($179). For the Time Capsule 1TB disk you pay an additional £90 ($120) which, for Apple gear, is not bad; but for the 1TB more in the larger model you are stung for an extra £150 ($200). That is silly.