The Mac seems to limit your choices when it comes to its appearance. Maybe that's what makes it “easy” to use. For example, I use a solid desktop background. What does Windows offer me? A color selection dialog that lets me choose one of 16,777,216 colors. What does Linux (GNOME) offer me? A color selection dialog that lets me choose any color, or a gradient between two colors (281,474,976,710,656 possibilities). What does Mac offer me? A choice of 10 colors. Four blues, four grays, one dark green, and one lavender. That's it. No reds. No yellows. No browns. No oranges. I guess Steve Jobs doesn't like those colors.
Update: [2006-08-07] There's a way to trick the Mac into letting you choose a color.
The color scheme is even more restricted. Classic Windows lets you separately color titlebars, controls, windows, tooltips, etc. There are 3, 121,748,550, 315,992,231, 381,597,229, 793,166,305, 748,598,142, 664,971,150, 859,156,959, 625,371,738, 819,765,620, 120,306,103, 063,491,971, 159,826,931, 121,406,622, 895,447,975, 679,288,285, 306,290,176 color combinations. On the Mac, there are two: blue and gray. On Windows though most apps don't really honor a lot of the color settings, so it's not a fair comparison.
My main complaint isn't so much the lack of choice as the usability issue. I use a custom Windows color scheme to highlight the active window. It's really important to me. (I also use a custom Firefox style to highlight the active form control.) I easily lose track of the active window. On the Mac, the active window has a gray titlebar with black text. The inactive window has a gray titlebar with gray text. The difference is subtle. It's hard for me to keep track of the window focus. It's harder to use, in order to make it pretty.
There's a great Mac app called Doodim that provides an incredibly useful feature for people like me: it darkens all but the focused window. This is better than anything I've seen on Windows or Linux. I love this app! Unfortunately it's somewhat slow on my Intel Mac because it's a PowerPC application, and it's running under emulation. I'm also using MenuShade, which darkens the menubar when you're not using it. I tried out some apps similar to Doodim (FocusLayer and Zazen) but they didn't work as well for me. I wish Doodim's functionality was built into the OS.
The Mac approach to limiting choice seems to be largely about the appearance. When it comes to functionality, it's much better. With keyboard shortcuts, the Mac gives me far more choices than Windows or Linux. I'm impressed (but I'd like a little more—there are odd restrictions on which keys I'm allowed to use). Underneath it all, the Unix (BSD) foundation is there and gives me even more power. I'm quite happy to see Python, Ruby, Apache, and so on installed (although I do wonder why they use old versions of Ruby and Apache). I'll take a while to get used to the differences.