i'd get the K30.
Why ?
The K30 has almost the same guts as the K5, plus an improve AF system (according to the first comments of the earliy adopters), improve live view and video fonctions, WR, etc ...
Now, the only thing the K5 have "more" than the K30 is few switch like Raw / jpeg, AF-S /AF-C, etc ... overall ergo is a bit better than the K30. But the ergo of the K30 is almost the same as the K-x, so you won't be any lost with the K30.
So, if, like me, you are always in the same file format and you don't change it often, if you always use the center point AF, and the center weight exposure, then the K30 may really be a better choice.
And it's getting cheaper
Just remember to pick a WR kit instead of the usual DA-AL (so, non WR) if you take the K30.