From a suffering BSD user...

[der Mouse]

> # oh the pain the pain.
> alias cd 'cd \!*; set prompt="$cwd:t[\\!] "'

somewhere[33] cd foo
foo[34] cd /
[35] cd ~/foo
foo[36] pushd ../bar
foo[37] pwd
/some/where/bar
foo[38]

Maybe you'd rather have /[35]?  Maybe you'd like pushd and popd to work?
Try

alias cd 'cd \!* ; fixprompt'
alias pushd 'pushd \!* ; fixprompt'
alias popd 'popd \!* ; fixprompt'
alias fixprompt \
'if $cwd:q == "/" set prompt = '\''/[\\!] '\'' ; '\
'if $cwd:q != "/" set prompt = "$cwd:t"'\''[\\!] '\'
-- 
					der Mouse

USA: {ihnp4,decvax,akgua,etc}!utcsri!mcgill-vision!mouse
     philabs!micomvax!musocs!mcgill-vision!mouse
Europe: mcvax!decvax!utcsri!mcgill-vision!mouse
        mcvax!seismo!cmcl2!philabs!micomvax!musocs!mcgill-vision!mouse

Hacker: One who accidentally destroys /
Wizard: One who recovers it afterward