I have a straight click key keyboard at home (which I really like), while at work I use a Microsoft Natural ergonomic keyboard 4000 (the one that splits the keyboard into two banks of keys), an OLD MS generic optical mouse, and two monitors.
I' m a developer and having the ability to full screen code or the ERD diagram and have the tool palettes floating on the other is a godsend. The keyboard is a great enhancement too.
Having used switch keyboards, mushy keyboards, flat key keyboards, etc., I have got to recommend a keyboard with good travel and good key "break" feel--that sudden release of pressure that tells your muscle memory the keystroke has registered. Back in the 80's Keytronics made the ultimate keyboard. It had perfect break and was otherwise silent. Built like a tank, the one I had lasted through literally a dozen computers! I'd still be using it if it hadn't had the original IBM PC connector.
The audible click is meh, I can take it or leave it. It's the keyboard FEEL that is more important.
And two monitors? A MUST for developers.
Mice? (shrug) as long as it isn't a hockey-puck, has two buttons and a wheel and is optical I'm happy.