For the last 6 months I've been using a Sun Ultra3 Mobile Workstation as the main machine for development for Cheffy (and more recently using the T2000 for actual deployment testing).

The Ultra3 is a superb little workstation, but definitely not a laptop,

One of the key benefits of this machine is that it is completely SPARC compatible - you can move binaries from the Ultra3 and run them on a SPARC server, for example the T2000, without having to recompile or redevelop the project.

For an engineer visiting sites, this machine would be ideal as you could use the software and utilities and copy them over with ease. For a developer, it certainly lowers the normal barriers of entry to be able to build and compile applications that can be deployed straight from the laptop to your servers.