If your .bash_profile does seem to be being processed, ensure that it is actually your login shell... Within /etc/passwd the very last parameter following your user account will specify your shell. If bash, make sure this reads ':/bin/bash'. Also, take a look at /etc/bashrc and inside /etc/profile.d for more clues as to why your environment isn't sticking.
To change your shell to something else, modify /etc/passwd and change the last line of your user account to the shell you want, i.e. :/bin/ksh or whatever. Check out /etc/shells for a list of available shells.
If hope this helps...