I've been using Macs more recently over the last six months or so. I've switched to using an older Macbook Pro at work. If I was getting a new laptop today, and had the money for it, I would get a Macbook Pro 13".
There are a few great reasons, IMO.
Hardware:
- LED display (though I don't like the glossy, you can get matte on the 15")
- ~7 hour battery life
- nVidia 9400M graphics
- Multi-track touchpad (no one else has this)
- Aluminum unibody (no one else has this, and the laptop feels SOLID)
Software
- Expose, multiple desktops
- Quicksilver! (download it, it's awesome)
- Excellent window management, taskbar
- FAR superior collection of system options/pref panes
I think the Mac is an especially great choice for a laptop because of the way your workflow is organized and the ways you can interact with it. New Macbook Pros have a very large, up to four-touch trackpad that lets you do a lot with just a few swipes of the finger. Laptops can be annoying because of the smaller keyboard/mouse workspace, but even the two-touch trackpad on my work Macbook makes my life so much easier.
Laptops also have limited screen space, which is where the window management comes in. I like using Windows on my dual display desktop, but on a laptop you don't have as many options for throwing windows around. Expose lets you see what you have open and grab it, multiple desktops let you separate out disparate tasks, and connecting these options to the multi-touch trackpad lets you scroll, move desktops, etc. very intuitively.
There might be a bit of a learning curve, but I don't think you'll look back.
I re-evaluated my opinion of OS X after spending a week working on the computer system at someone's office. They had an all-Apple product setup, and I found that it took me less time to figure out the interface AND solve problems than it would have taken me to just solve problems on Windows-based machines, which I know very well.
Edit: one more thing. I would recommend adding one of the current generation 7200RPM notebook drives. I think you'd see a good difference - the 5400RPM drives they put in Macbooks seem optimized for noise/vibration/cost more than anything else.