Nice
Although it is nice to see such review, i think you miss some point.
As far as i know, there is very little to no difference between single dual and triple channel mode. So even if you do own i7, you can still live with normal dual channel kits. this will give you some flexibility with amount of memory.
The second point is that as you shown, there are few applications that can utilise (benefit) from large RAM. I can think only about large projects in CAD applications in addition to Photoshop. But if we put benchmarking aside and come to real life world, my guess is that i'm not the only person that does not like to restart computer. Smaller number even take one step further and do not close applications since they probably will want to use them again before restarting the system.
In this scenario you can end with slow and unresponsive system if you don't have enough RAM.
I have only one computer with MS OS and it is Win 7 64 bit with 3 GB of ram.
2x1GB + 2x512MB. It is used as my personal desktop at work. The most Used applications are Browsers and Office suits. If i open 1 tab and one document it is not a problem. But usually after few days after restart i endup with 20+ tabs + 2-4 Text documents , 1-2 presentations and 2-5 spreadsheets. Of course there is antivirus , music player, VMware infrastructure client, Visual Studio, Source and bug control software and others.
Each one can run fine on 2,1 or even 0.5 GB setup. But put them all together and i find myself looking what can be closed in order to make system more responsive. RAM usage is usually above 85%.
Rest of my computers are Linux based and can't be directly compared to MS since memory management is different and OS memory footprint is significantly lower. (less then 100MB with at least 600MB for vista and 7).
So the benefit from large RAM depends on usage pastern.
Another aspect is RAM disk which is very nice, but i cant see how it can be implemented with 10+GB vista and 7 installation. So it's more for NIX users.
To summarise, for most of us it is nice/must to have 4-6 GB for comfortable usage. Those with special needs like CAD or Photoshop processing large files should get as much as possible.