If a la carte were to be implemented, I'd expect it to play out much as I understand it already does north of the border: once you get past the basic tier, you can select individual services - but by the time you've picked more than a handful of those individual channels, you'll find it cheaper and easier to buy a packaged tier of channels.
If you really truly only want to ever watch six channels, maybe you'll come out ahead, but my guess is probably not by much; if a la carte is ever implemented, count on the cable companies finding some regulatory way to levy something similar to the "distribution charge" that now shows up on my power bill every month. Sure, I have the "choice" of several different electricity providers - but the company that actually delivers the electricity to my house still gets a fairly hefty chunk of the bill regardless of whether I use one kwh or thousands of 'em.
Be sure, too, that there will still be some sort of bundling: it's hard to imagine an a la carte regulatory scheme that would prevent ESPN, let's say, from offering ESPNNews, ESPN Classic and ESPNU for a tiny nominal charge to anyone who buys ESPN and ESPN2 at "full price," and who's to stop them from setting the "full price" of main-channel ESPN at a level that's still sufficient to cover the incremental cost of running the other networks in the bundle?
The experience of the cell-phone carriers is instructive here: maybe I only send 62 text messages in the course of a month - but the vast majority of wireless customers who text, given the choice, would rather pay for a bundle that includes "unlimited" texting than worry about running up the meter by paying "a la carte" per text.