I would try Futura (maybe set in small caps*). Or Nobel. Eventually Avantgarde Gothic.

*http://www.fonts.com/findfonts/detail.htm?productid=371482

edit: Different direction – what about Graphik?
http://commercialtype.com/typefaces/graphik

Try the stationery.
Especially the business card.
Or a small space ad.
Can you work with the figures, italics, small caps in a typeface?

… a geometrical sans serif font.

Avant Garde is intangible for decent designers.

Futura and Gotham are fine faces, yet desperately over-used.

Look for alternatives. You may consider e.g. Brandon, Avenir, Mostra (Nuova), Eagle, Kabel, Le Havre or, if modesty allows,
Lapidaria.
Good luck!

"...Futura and Gotham are fine faces, yet desperately over-used."

I completely agree with your comment, and that's why I wanted to look for an alternative. Thanks for the suggestions, I'll look into them!

Unless I'm mistaken, the word on the street is that H&FJ are going to be releasing Ideal Sans this week. It's a humanist sans, but it may work very well with what you're building. To get a feel for the flavor, see their Topaz (the 'background' and 'inline' variations, not the default built-in inline version). Ideal Sans is built from the outlines of Topaz (or maybe it was the other way around, considering Ideal was originally designed some 20+ years ago). Good luck!

I agree on Avenir and Brandon Grotesque, and would also like to add Neuzeit S and its progenitor, Christian Schwarz's Graphik — another wonderful option for a versatile, geometric sans.