i think this is more $$$ question, if you can afford K5 then go for it. If you can`t, then go for K-r (it`s really a nice camera).
Since you are not invested in Pentax system, you can also look for other brands, but i don`t think you will find something comparable to K5 (maybe Nikon D7000, but it`s not Pentax
maybe also canon 7D (i would not go into Canikon lowends, because they are really budget cameras.) If you will stay with Pentax, i think you will be more than satisfied. Mainly when you will get better lens than kit lens.