I've always been a fan of IBM model M keyboards. I worked with one for some time and additionally had the luck of having very forgiving coworkers with plenty of patience (eh Noyda??? :-), because, you know, they are certainly noisy.
The one I have doesn't work very well with my Mac and IBM stopped building them a long time ago. But fortunately a company called Unicomp purchased the license to build keyboards with the same technology, I knew about Unicomp and their Customizer from this positive review and ordered one right away.
Bingo, an excellent keyboard with those lovely mechanics and feedback. The PACK! of the return key is exactly the same, it sounds unique! It has been a few days since it arrived and man I love typing with this keyboard.