Hi,
Well im on a dial-up modem too, a 56kb that is.
Im currently using Arch Linux 0.6, ive been using it since 0.5 was released (expected the release over a month) and im about to get 1 full year of using it.
Its one of the best i have tryed, and i did tryed a lot. (MDK, SuSE, Slack, Knoppix, Morphix, Damn Small...)
Its binary package management is one of the bests out there, although the pkgs it self some times are a little buggy (the price of cutting edge, though you can stay with stable instead of current if you dont like it), to make an upgrade to all your installed packages you just need to run one command:
pacman -Syu, this means; sinchronize, refresh and upgrade. Also for installing other pkgs in the repos, just do
pacman -S pkg-name and thats it, it will handle all the dependecies, download and install all you need.
Anyway, in my opinion, Arch is in its way to becaming one of the great distros out there.
Give it a try:
www.archlinux.org
Updating the pkgs (if you want) daily, consumes less than 10mb of bandwidth --most of the times, except for big updates as X, browsers and such--.