Great job, champ. You've chosen wisely.
The default settings in Terminal will work well enough out of the box, but for completeness, I'll list the requirements here.
If you want to play with the new NCurses interface:
160+ column terminal MUST be set BEFORE telnetting. (A bug in how dgamelaunch and ncurses interact prevents terminal-resize messages from being received)
For all interfaces' settings:
UTF-8 Default Encoding (!!!)
Allow bold text
Monospace font
White-on-black default text
After all that, just `telnet nethack.csh.rit.edu` (or click this link).