The answer you want is a Land Line coupled with Plantronics SHR2083-01 Industrial Noise Canceling Headsets. I've put these into the last 12 cage buildouts I've done. The mouth piece isn't great, but at least it's audible when you're standing right in-between two 20-ton CRAC units. Don't do a cell phone, life is too short. Avoid VOIP because you can't call up and talk to a vendor if your network is down.

For 8 years, I ran Linux on the desktop, because I was a geek and that's what we did. Then one day I was doing work at a customer site, and my laptop died. I grabbed a spare imac to finish up my work, and was very impressed by the experience. The next day I went online and bought a powerbook, that was 4 years ago, and I haven't looked back. Linux runs on the 350 servers in my datacenter, but not a single machine in my home anymore. I'd never consider OSX for a server, and I'd never consider Linux for a desktop. Computers exist to help me run my company, I don't exist to run my laptop.