I've just got a new mouse for my computer at home, and I'm really pleased with it. It's a Logitech VX Nano cordless mouse, and I got a really cracking deal on it from Amazon. Despite the abomination that is the Logitech Control Centre, I quite like Logitech mice, and I've had a variety of them over the years. My work mouse is a MX 1000 Laser, which is also good, but has a tendency to 'skip' a bit sometimes.
What I wanted for home use was a compact mouse with a small receiver that I could easily travel with when my laptop and I are on the move. I also wanted a mouse which has an 'off' switch: the previous one didn't, and ran through batteries as if they were going out of fashion. Buying a mouse without being able to handle it is always a little risky, but I felt fairly confident that I would get on with it. Now, I have Tiny Hobbit Hands, but have always used quite big, chunky mice and felt comfortable with them. The VX Nano is small, but with my fingers on the buttons, my palm sits quite comfortably on the top of the desk in a natural position.
The tracking is excellent and very precise (much better than my MX 1000, actually), and the extra buttons are very useful, as you can remap the functions with the software. I've mapped the forward and back buttons to forward and back in Safari and Path Finder, and the switches which activate when you rock the scroll wheel from side-to-side trigger the keystrokes for the next/previous tab. The software now allows you to set up different mappings for different applications, which means that I can have the same button action to navigate through tabs in Textmate and Safari, even though the keyboard shortcuts are different. Very handy.
The best thing about the mouse is the scroll wheel. By default, it behaves like any mouse wheel, with 'notches' for each increment of scrolling. However, if you press the wheel down and release, it goes 'frictionless' (almost -- obviously it can't break the laws of physics). It's hard to describe how cool this is, but you can flick the wheel to scroll very quickly, or move it gently to scroll very precisely in small increments. The receiver is also incredibly dinky, so that you can leave it plugged in to a laptop all the time, without worrying that you'll snap it off accidentally. I've plugged the receiver into the USB port of my wired aluminium Apple keyboard, and it is completely invisible from the top. When you travel with the mouse, there's a little slot for the receiver inside the battery compartment, which also turns it off automatically. All in all, it's a very nice mouse.