I generally keep several batches of beer around (in bottles) and enjoy whatever I'm in the mood for at the moment. Sometimes I even go days without a beer (gasp)! It seems to me that were I to keg, I'd end up with fewer varieties on hand and cold. I mean, really, who has room for an 8-keg cooler in their living room? While 24 bottles in the fridge take up little space, letting me indulge in up to 3 bottles of any given variety.
My other concern about kegs is the waste. If there's been beer sitting in the line for several days, that's gotta not be good drinking. So don't you have to let the tap run a bit before you get to the "good beer," the stuff that's fresh and cold from the keg? How much beer do you let run to the ground each time?
I do see that for some occasions, kegging would be better. If you were brewing for a party and expected to serve most of a batch in one day, for example. It would definitely be a more efficient way to accomplish the task, and save labor as well!
But for my day-to-day casual use, I don't see kegging as practical.
[EDIT]
It occurs to me that my space argument is specious. I've got 5 large tupperware containers filled with bottled beer inside the house, and another 3 giant containers full of empty bottles outside. Plus a couple of cardboard boxes to handle the occasional overflow, whichever side it occurs on. Maybe if I were to clear all that crap out, a kegerator would actually give me MORE space.