[samloveshummus]

That's not exactly right; in British English and other dialects that don't say "legos", we don't have a plural of "lego" because we treat it grammatically as a "mass noun" just like "furniture", "spaghetti" and "advice".

"Legos" sounds wrong to us not because we care about the brand identity, but for the same reason that it sounds dopey to say "I love your furnitures", "These spaghettis are tasty" or "let me give you two advices".

[mos_basik]

Huh. Wonder what kinds of forces drive the pluralization (or lack thereof) of nouns in English dialects? Your comment reminded me of another one that sounds odd to my American ears: "maths," as in "Tommy's always been very sharp at maths."

[Handytinge]

Oh yeah, Americans saying maths wrong really grinds my gears. Why use a singular? It's not short for mathamatic!