I think the most important thing for next gen consoles is to bump up the RAM. Of course developers will always be able to make use of more processing power, but all the little tricks that can be utilized to great effect, like tesselation or high res textures, require more RAM than the 512MB combined RAM in the PS3 (256MB system+256MB GDDR3) or the 512MB GDDR3 in the 360.
I think the most important thing for next gen consoles is to bump up the RAM. Of course developers will always be able to make use of more processing power, but all the little tricks that can be utilized to great effect, like tesselation or high res textures, require more RAM than the 512MB combined RAM in the PS3 (256MB system+256MB GDDR3) or the 512MB GDDR3 in the 360.