I recently said that I thought the current "standard" pixel dimensions for ads are ridiculous. 728x90? 88 x 31? Wha? I have a new idea: ad sizes that make sense.
Let's start with a basic building block. 125x125 is very popular, already a current "standard", and supported by a wide variety of ad networks. So if we start there, and chose a reasonable gutter size (10px), we can build a whole system of ad sizes that make sense.
Using just this block and the 10px gutters we can get a whole bunch of rational sizes:
Our 125px building block is also divisible by 5, making 25px.
So, we can substitute and multiple of 25 (e.g. 25px, 50px, 75px, 100px, 200px, etc) for heights as needed. Need more of a button size: how about 125x25px?
If I were to build a new site that incorporated ad sizes, I'd definitely do this (or something very similar), rather than try to "accommodate" old ridiculous sizes like 728px that have nothing to do with anything. And besides, if an advertiser can't be troubled to make an ad to a specific and rational size, we probably aren't going to be a good match anyway.