These are the two desktop environments i was using during my practice. These are also the ones i used in the CCIE Lab. The only difference is that i used Putty during my practice (it's the lightest telnet client and it's free) vs SecureCRT in the CCIE Lab. But since i knew i was going to use SecureCRT in the lab, i spent 1 hour on practicing with it, just the day before my flight to Brussels.
That way you can copy-paste (left=select/copy, middle/right=paste) between windows very easily/quickly and most importantly you can watch half of your equipment all the time (R5,R6 are half covered, so you need to click on them in order to bring them full in front). i.e. when you change something on a router/switch, you can see immediately if there is a log produced on another router/switch. You cannot do this when using the terminal server.
All the windows have the equivalent router/switch name as their title, so it's very easy to select which one to have on your desktop every time. In a screen of 1280x1024, i used 82x28 (columns x rows) as the size of the windows (you can start from 80x25 depending on your desktop resolution and font used) and "courier-new 9" was the font and font-size.
I also used black background and white foreground (default in Putty, had to reverse in SecureCRT), because those seemed the most relaxing colors. If you have to look at these windows for 8+ hours, you need to take care of everything, even your own eyes. You need to have the whole environment cooperate with you, not fight against you.