GPU mining as I type is more profitable based on price of the coins over the cost of equipment when you factor in longevity of the hardware due to diff potential rise.  the cost of electric, won't be a factor for the next few months for GPU or Asics, his won't come into play again until march 2014, when 1st batch Avalons will start to become obsolete, followed by BFL's, blades and USB asics.  As we all know this will be a game of attrition, In the end mining will only be where electric is free.  

Now...
£2500 gets you (Saturn) 330Ghs = 0.25 BTC a day = £164

£2500 gets you  (13 x 7950) 7000Khs = 5 LTC a day = £110

in 3 months the drop in returns for the Saturn will be much higher that the drop in the 7950's, unless there is some new hardware which is doubtful in that time scale.  Over a 3 month period a GPU farm would be more profitable IMHO and will remain so for longer. Also the GPU will have sell on value after it becomes obsolete for mining.    Of course none of this can be taken seriously, there are just too many possible factors to account for that we have no control over, because tomorrow BTC could be $10000 and LTC $10. As it stands, GPUs look more attractive to me. If LTC does end up as .25 of a BTC what then?  those 100 LTC start to look a lot more attractive and it will be another case of people looking back and thinking "what if"...

I for one won't be buying a Neptune (can't afford it at the moment).  I will wait for a credible Scrypt asic or fpga to emerge, it won't be long now.  and as soon as it does happen and GPU's are no longer effective, scypt-jane coins will get all the GPU power.  

Just my thoughts.

KnC any new plans for a scrypt-fpga?