Mac laptops are good, but expensive and I don't know if they'll be trouble-free for you if you need to "speak to basically everything out there".

You can get inexpensive Mac laptops if you're willing to use something that is a few years old. Check out eBay and [link|http://www.macofalltrades.com/Apple_Notebooks_s/5.htm|Mac of all trades]. My wife has a 667 MHz Titanium PowerBook G4. It runs OS X pretty well, but it has over 1 GB of RAM and a faster-than-stock hard disk. It runs MacOffice98, but can't run a modern virtualization tool like [link|http://www.parallels.com/|Parallels].

I've had good luck with [link|http://www.mepis.org/mirrors|MEPIS] on this T41 laptop. But I've only played with it - I haven't used it for real work. I haven't tried the latest version yet. I didn't have as much luck with previous versions of Ubuntu, but YMMV.

The good think about the latest MacBooks is that they're on Intel processors so there are lots of virtualization choices.

If money's no object, get a MacBook or MacBook Pro. If compatibility is the primary concern, get a PC laptop and Linux and run to run Windows as a client. (You can do the same thing with the MacBook, too.) Parallels needs an Intel processor, so running it on a G4 PowerBook isn't an option.

HTH a bit. Good luck!

Cheers,
Scott.