One of the things I bought with my Aperture rebate was a Logitech Cordless Desktop S530. At home and at work, I use my 12" PowerBook raised up on a stand with a separate keyboard and mouse, so I've got a number of input peripherals scattered around that I have varying degrees of affection for. Both keyboards and mice are very personal things, and I find that it often takes a while to find out if you're suited to one another. I'd seen good reviews of the S530, and I generally like the shape of Logitech mice, so I thought I'd give it a go.
I've been doing a lot of writing for work using the S530 in the past few days, and I like it a lot so far. The keyboard has a pleasantly positive but 'clacky' feel, and the 'zero degree' tilt and integrated palm rest feels very natural and comfortable. Unlike a lot of keyboards, the rubber feet underneath stick it to the desk like a limpet, so it feels very solid and secure to type on. The extra built-in buttons (for Mail, Safari, iTunes, Spotlight and iPhoto) work quite well, but I don't know home much I'll use them in the long run. Having dedicated play/pause and next/previous track buttons for iTunes is quite handy though.
The mouse is Logitech's usual large, curvy shape, with a groove for your thumb, forward/back buttons (handy for web browsing), and vertical and horizontal scroll. There are also tiny buttons for volume and mute that I'll probably never use for that purpose, but I could remap them to trigger Exposé I suppose. Despite my tiny Hobbit hands, I find the shape and size of the mouse very comfortable, and the buttons and scroll wheel all fall nicely under my fingers.
Logitech makes nice hardware, but their control software is pretty poor. The current version of Logitech Desktop is just about functional, but badly laid out and rather limited. For example, I'd like to remap the horizontal scroll buttons to move forward and back tabs in Safari, but that's not possible. Despite this weakness, I'm very pleased with the S530. I'm almost tempted to buy another for work so that I can get used to the same key layout and feel in both locations.