From what I've read it seems the consensus is generally <11:1 and really more like 10.5:1 or less. I was thinking of shooting for 11:1 myself but the more I read the more I'm thinking 10.5:1 or less is where I'll end up.
Now if you extend your "pump gas" to include e85 then you can jump the compression up quite a bit, e.g. 13:1+
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John