We are looking forward to installing Leopard on our Macintoshes here at Joyent this weekend. We talked in the recent episode of ps pipe grep about the effort at Sun to ensure Solaris is a good operating system for laptop computers. (Cricket sounds).
But seriously, now that OS X 10.5 (Leopard) is shipping (today), with DTrace probes for Ruby from Joyent, Macintosh laptops, now more than ever, are the platform for web application development. Especially Ruby/Rails applications.