As good as HHKB is for Unix coding and scripting, it's VERY annoying for Visual Studio stuff, so please be careful with recommending it for programming not knowing what person is going to program with.
So with all seriousness, if you don't look for flashy show off piece, but something that will make you more productive and less tired, you should consider:
- Any Costar/Ducky fullsize/tenkeyless with a switch that suits you.
- Realforce in a layout that you prefer, be careful with 55G though as it's seriously tiring if you use it for 8 hours workdays 5 days a week.
- Either classic Model M if you can find a well preserved one or can spend some time cleaning and possibly bolt modding, or of course Unicomp, it may also need some modding to get right though.
- ErgoDox if the layout works for you. It has enough keys to program just about anything + some fancy stuff like mouse keys and what not.