I've been thinking about getting a "proper" (expensive, mechanical) keyboard for a while, I'm getting close to a requirements list:

• ISO-UK layout (deal-breaker)
• Wired (deal-breaker, work security rules require it)
• "Brown" switches (Tactile (have positive 'yup, I've been pushed' feedback) but not clicky)
• Number pad
• Media keys (at least play/pause, volume, next/previous)