looks pretty sweet on black as well, personally i think a white background is preferable because its simple easier for business cards etc but you could always use a black background version for web depending on the site colouring
and the black and white version, all logos inevitably have to appear in b&w at some stage so its important to keep that in mind as some logos look completely different when done in black and white. This one however, is as strong as ever when reduced to monotone =)
#32 I like this one too. Could I see this one with the grid element in a color instead of gray and maybe the text a little larger with some shadowing effect?