I bought a Mac two years ago for iPhone dev (which I ended up not doing), and in my opinion you don't have to switch to a Mac if you are already a Linux user. I still prefer Linux.
The only problem is buying any other notebooks that are good. It is very difficult to find notebooks with acceptable design and specs.
I have to say I am not a Mac power user. I am too lazy to learn gestures (and hence don't want to update to Lion, either). I never use the F3 to show the desktop because I keep forgetting the key (Linux and Windows have clickable icons in the taskbar, much better for me).
May I suggest you look into "Hot Corners", which is built into OS X and allows you to specify certain actions when moving the mouse to the very corner of the screen.
I heavily use the gestures, but I still find these rather handy
My setup is;
Top Left: Show Desktop
Top Right: Expose (on Lion, Mission Control)
Bottom Left: Blank Screen (without sleeping)
Bottom Right: Screensaver
Hot corners seem like a terrible idea, simply because they're far too easy to acquire (by Fitts' Law). I don't want Expose or whatever to show up every single time I move my mouse to the top right corner, which is often accidentally.
I've had this setup for years now, and never accidentally done this.
Don't forget on a Mac you're much less often moving your mouse to the top right corner (window closing is on the top left of a window.
The further most icons are always the Apple on the left, and Spotlight on the right. Both of which I rarely open by hand. If I'm using Spotlight it's always by keyboard command Cmd-Space (though often I use Alfred instead).
And at least on a Laptop I rarely need to shutdown the Mac, which is all I'd use the Apple menu for. Though again, anything I'd go to that menu for I use Alfred for instead.
May be worth turning it on and see how you get on with it?
The only problem is buying any other notebooks that are good. It is very difficult to find notebooks with acceptable design and specs.
I have to say I am not a Mac power user. I am too lazy to learn gestures (and hence don't want to update to Lion, either). I never use the F3 to show the desktop because I keep forgetting the key (Linux and Windows have clickable icons in the taskbar, much better for me).