I'm thinking about purchasing a new 27" iMac 2.66 Ghz i5 or the 2.8Ghz i7 option, but I would like opinions about how much faster it would be compared to my 4 year old Quad 2.5 Ghz Power Mac G5. My Quad 2.5 G5 has 4Gb of ram and a Nvidia Geforce 7800GT GPU. For comparison this setup is faster in almost every single way compared to my Unibody 15" MBP 2.66Ghz Core 2 Duo, 4GB RAM, with 9600M GT. In many cases the G5 is easily twice as fast, and in few Rosetta app situations it is 3-5 times faster. So the question is, if I replace my Power Mac G5 with a new quad core i5 or i7 imac, will I finally see performance gains that could justify replacing my trusty G5 or must I buy a new mac pro to see performance gains that are considerably better. I would rather not purchase a quad or Octo core Mac Pro as the imac seems to be much more cost effective, however I have not been able to find any benchmarks that effectively compare the Quad G5s to the latest Intel offerings. Any advice or opinions would be helpful.