For reference, I wear an 11 in Nike, 10.5 in Converse and Sperry, 11 in Clarks DB (although I should wear a 10.5), 11 in Cole Haan and a 10.5 in 1K's.
Everything other than 1K's are with regular socks. I wear midweight wool socks with 1K's. I initially bought 10D in the 1K's but they were too tight, even with thin socks.
On another note, the 10.5D Alden Indy in True Balance felt significantly narrower and smaller than the 10.5D 1K.