Possibly my old IBM Thinkpad keyboard if possible, I utterly despise Laptop keyboards, partially the reason i never got a new laptop cos all the keyboard layouts on newer ones suck.
Though i also have some old PS/2 keyboards like the IBM one that came with my original Aptiva back in the day, or a cruddy old chicoy one that may actually be interesting to mod since it has extra keys.
Though if i didnt already have the Sun keyboard and had known about keyboard modding and construction earlier i'd have built a keyboard with the sun type 7 uk layout myself with a slight addition of a menu button to the right of the right super key and f13 -f24 keys
In the future possibly something retro, always thought the classic keyboards like the BBC Micro keyboards were cool, or the rubber ZX Spectrum keyboard though i'd only turn those into keyboards if the main computer they were built into was beyond repair.