[adrie]

What do you consider the best yeast for a Russian Imperial Stout (and why)?

[bluesman]

What do you consider the best yeast for a Russian Imperial Stout (and why)?

I like to use S05 because it ferments that beer down fairly well.  You want to use a fairly attenuatifve yeast considering all the unfermentables and the size of the beer. 

[chumley]

I like Ringwood because I like the fruitiness from the yeast paired with the malty sweetness and roastiness from the wort.

Commercial example:  Try a Carnegie Porter sometime.

[jaybeerman]

wlp-051 - nice overall american character with subtle fruit esters, for my hoppy imp stout

wlp-028 - malty with a whole spectrum of yeast character, think savory rather than sweet

wlp-007 -  not my fav flavor profile but this is a workhorse of a strain, very good just not my personal fav

[Beertracker]

I'm a split w/ Chumley & jaybeerman:

WLP051/WY1272 - Love the intangible character & fruitiness it brings combined w/ the darker malts. Winner, winner chicken dinner!

WLP007/WY1098 - U just can't mess w/ success. Classic strain for fermenting this style! Try a 20yr. old John Courage RIS sometime.  

WLP005/WY1187 - The "dreaded" Ringwood Ale (a.k.a. Swedish Porter) strain. Great... IF you can get it to perform in the fermentor. The "original" Baltic yeast strain.

Can't go wrong with the first two for certain... the latter will do even better with a big starter & open (shallow) fermentation. Good luck!