A) So if a Str 18 Eladrin Fighter with the feat Eladrin Soldier used Sure Strike (no Str bonus to damage) while wielding a +1 longsword two-handed, how much damage would he do?
B) How about if he attacked with Brute Strike instead?
The way I figure it:
A) 1d8 (longsword) +1 (magic) +1 (versatile) +2 (feat) = 1d8+4
B) 3d8 (longsword) +1 (magic) +1 (versatile) +2 (feat) +4 (strength) = 3d8+8
Page 276 has a pretty clear example - only the rolled dice (both normal damage and crit) get multiplied.
This means that attacks that give you multiple hits at 1[W] are usually better than ones that give you a single high-damage hit, as you get the secondary bonuses multiplied by the amount of hits.