iMac - Apple Pro Keyboard with a Microsoft Intellimouse Explorer 4.0. Most comfortable.mouse.ever. Sometimes I whip out the Mighty Mouse for multimedia/time-based work though.
MacBook - built in keyboard and usually the touchpad, though I bring along the Mighty Mouse from my iMac mainly because it packs in a bag easily.
I use the keyboard on my 12" PowerBook (one of the main reasons I got another PowerBook over a MacBook) and a Microsoft optical mouse. I've used other mice in the past and I've always come back to Microsoft ones. They just feel right. I carry it around with me everywhere because I don't like trackpads too much. Though the new scrolling feature goes a long way to rectifying that.
I use the built-in in stuff on my MacBook. On my iMac I have Apple's included keyboard and a Logitech S 530 Laser mouse.
When I'm not out and about with my PowerBook, it sits on an iCurve at my desk and I use the standard white Apple keyboard and Microsoft IntelliMouse Explorer (which I love, but I need to get in a wireless
version). I'm actually in the market for a new keyboard due some wrist pain I've been having, so I've been looking at the GoldTouch Mac from KeyOvation.
As for me? On my home and office desktops I use the Matias OS X keyboard. The symbols are great for me since I always forget where they are. The extra control key and the caps-lock key being out of my way is a blessing and I really love the action on it. I'm a big fan of tactile keys - and this one is quieter than a typical tactile keyboard, which makes hubby happy, but it's still "clicky" enough to make me happy. My mouse is a 5-button, rockin' tilt-scroll Microsoft Wireless Intellimouse Explorer, which I would be lost without. When I'm on the PowerBook I generally stick with the built-in keyboard and trackpad since I'm typically on-the-go and it's just easier that way.
Hmmm... 4 out of 5 bloggers agree that what Microsoft lacks in the OS department they make up for with their mice, which rule. We don't agree on much around here so that's about as resounding of an endorsement as you're going to get from us.
Now it's your turn -- What mouse and keyboard are you using with your Mac(s) these days?