I'm looking for a Latin translation of the saying

"All things in moderation and moderation in all things."

"Res omnia moderatie et moderatio rebus omnibus" is what I'd use. You
could make this shorter though (and much more difficult to translate
into English) by saying, "Omnia moderatie et moderatio omnibus." (This
is more difficult because you have to figure out what kind of ablative
moderatie and omnibus are, and you have to realize that omnia and 
omnibus are referring to generic "things.")

Yeah, actually I like that second one better. I also forgot to
mention, if you want to make it really easy to translate into english
you could say, "Res omnia en moderatie et moderatio en rebus omnibus,"
but I doubt any Roman would have ever said it that way. Not that I
know personally though, just from what Latin context was engrained on
my brain in school. Also, you should note that these declensions are
pretty irregular, and not many Latin-takers would immediately be able
to parse this phrase, although they would probably get the meaning of
it pretty quickly.

Do these help you with "what kind of ablative moderatie and omnibus are"?

From Cassell's Latin Dictionary
moderor -ari deponent (and modero -are, act :Pl)
omnis -e, all, every, whole. per omnia, in every respect (from Cicero)

I'm not sure how to read these entries, but maybe the info you're
looking for is there.

Oh, that wasn't a question. I meant to write, "...you'd have to figure
out what kind of declension moderatie and omnibus are, namely,
ablatice." Thanks for you input though.

A comment on Purkinje's proposed translation...

The ablative of "moderatio" is not be "moderatie."  

It's "moderatione."
://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&c2coff=1&q=%22de+moderatione%22&btnG=Search

Oops, thanks juggler. "Omnia moderatione et moderatio omnibus."