Hi there! I'm debatting whether to get the 2.4 GHz/8 GB, the 2.4 GHz/16GB or the 2.7 GHz/16 GB version. Apart from daily usage as MS Office and surfing I'm planning on using it regularly for statistics with SPSS (large datasets) and photo editing with Lightroom/Aperture. In what way (if at all) would I benefit from getting the higher end model? Thanks for your suggestions.