After four months, or 32 milongas, of trying to create an evening with more "analog" methods (i.e. CD's) I'm certain that no system of CD's can ever achieve the quality in an evening possible using a laptop computer.
First of all, CD's are less holistic than a computer can be. You cannot adjust their relative volume on the fly. You cannot rearrange them on the fly, you cannot preview them easily ... but most importantly, absolutely, is that when you make a discovery, you'll lose it, if you don't write it down. And even if you do write it down, it is out of context, and you have to try to re-create the evening from your head or your notes ...
I've seen quite brilliant DJ's, like Alex Krebs & Robert Hauk, try to do this. The more I listen to their evenings, the more I feel they are limited by their technology. And what if someone is less brilliant or educated than they are? I don't know as much about musical structure as Alex, so I need to listen carefully, and make carefully considered Tandas, with careful notes, integrated with the music files. Otherwise I'll just forget good stuff, and I won't be able to improve bad stuff.
The cortina problem is typical ... some cortinas simply fit beautifully between two particular Tandas. But you don't always want to play those two tandas in a row. But having the same music on multiple CD's is maddening. I've tried it. It kinda works, but it doesn't work well. You'll end up limiting your range to compensate.
It's back to a laptop for me. A solid DJ laptop, the low-end iBook, isn't that expensive these days. But we'll be setting up a desktop (or two, for pair dj-ing) at the Tango Center's DJ station, so people can arrange their own playlists. And share their playlists with each other ... borrow & learn.
But I still believe real
analog can beat digital ... live music: for dancers, for tango.