I was thinking white could be a fun addition (particularly if you already have some tan sandals), but the particular style of these is pushing me back into tan camp--these are quite strappy, almost "cage" style shoes and therefore I'm thinking you may prefer them in a more neutral color that doesn't jump out as much as white naturally does. I like the white ones that Aida pictured, but you'll note that those are a more simple sandal style and so you notice the white but it's not overwhelming. I'm afraid that the style of these wouldn't lend themselves to the same effect, if that makes any sense.
Also, what is the ebay return policy on these? I know you've written previously about getting stuck with items you can't return (because they were a better price) so just wanted to flag that. If you can't return them, I'd defnitely purchase from a return-able source, even if they end up being pricier. Shoes are particularly tricky that way...