I have the opportunity to buy an iMac at a reasonable price! I'm not sure whether or not to go for the i5 or i7? My main program is Lightroom 3 and a tiny bit of CS5. Presently my Raw images are only 10mb, but in the next year or so I hope to upgrade to a Canon 5dmkII which has 21mp images. Will Lightroom utilise hyper threading? Is it worth spending the extra for "future proofing". Whilst the difference in price is roughly £100 after I have sold some bits, it is still £100! I currently have a 2.66 i7 MBP and don't need the portability anymore.