I've got good experience in Java and web development with some experience in C++ also. Lately, I've been thinking of leaving Java (bored with it) for C++. Then came Python(didn't like Ruby). I find it too good to resist and started using it. But the C++ still stays in my mind. 
Now I want to "stick" with one language to be fluent with it.
Python is great for quick programming but its too easy and I fear it would dumb me down. C++ is tougher but I doubt if I should use such a language where more time is wasted in keeping the compiler happy.
Which language should I stick with. Any comments?
I'd suggest looking into a more esoteric language, at least for a little while.  Write up a small GUI in Smalltalk, or a utility in Common Lisp or Scheme.  Don't just try to adapt your Java knowledge to those languages, really try to use the languages the way the Ron Jeffries and Paul Grahams of the world use them.
If you just want to learn something applicable in the job market, then those won't be as good as Python or C++.  However, learning languages that are very different from languages that you already know should provide an interesting challenge, and permanently alter the way you think about programming.
Which language should I stick with