My office is filled with great, old machines. A nice SPARC20, an SGI Indigo2, a NeXTSTation, a Canon ObjectStation - lots of cool old hardware. But to be honest, it's not anything like my laptop or iMac for speed. I hardly ever use them. They are using power and heating up my office, and it was time to realize that they were my friends, and I'll try to hang on to them, but they are past time to retire.
I turned off five of them. I left on my two iMacs and a computer that's nothing but a print server, and as soon as I get new desks for the office, I'll put the printer on the G3 iMac and turn that guy off too. I'll go from nine to three. Big difference.
The heat will go away... it's already tons quieter, and I really haven't lost anything. I've got a lot more space in my office, and the new tables (from IKEA) will make it possible to put in a nice little loveseat that will be nice to sit in when I'm working on my laptop. Face it... that's what I do for 90%+ of the time I'm on a computer in the day.
If I get a new Mac Pro, I'll have room to put it in the new space, but at over $6,000 for the kind of configuration I'd want, I think it's a lot more likely that I'll just be upgrading the laptop when the new ones come out and leaving it at that.
It's a big change for me, and I'm a little sad about the silence. But at the same time, I'm excited about the possibilities.