Core i5 - any degradation from 2-channel memory?

According to Tom's Hardware:
Performance loss triple -> dual channel avg. 0.6%, triple -> single channel avg. -2.1%:
http://www.tomshardware.com/review [...] 57-13.html

A difference, but hardly a massive one.

As far as memory bandwidth is concerned though, you're wrong about the first statement. i7 has more than double the memory bandwidth of the best Core 2 Duo setups (or core 2 quad), and memory bandwidth scales pretty much linearly with channels for a given controller. I would expect the dual channel i5 to have pretty close to exactly 2/3 of the bandwidth of the i7 with the same memory, but I wouldn't expect it to have much effect on actual performance of programs.

While on the subject of memory:
The Tom's Hardware test on DDR-800 vs DDR-1600 shows about the same - having twice as fast memory almost doubles memory bandwidth, as expected, but with a couple of exceptions this is hardly noticeable for most applications:
http://www.tomshardware.co.uk/memo [...] 00-10.html

I guess this means that on modern hardware very few desktop applications (including games and video encoding) are limited by memory bandwidth.

I would imagine memory bandwidth becomes more important if you are running something like a web server?

Thank you all for the input. The key piece of information for me is that the lesser memory bandwidth does not have a major impact on application performance, although it does have a measurable one.
TDP may be my deciding factor - I want a quiet machine in my home office. It's also the warmest room in my house (why I was allowed to have it!), and the less heat thrown the better.
Strangely, the main reason I want a new machine at all is to play with benchmarking RAID arrays.