I would say arch linux but I see you already tried and found it too hard to install a decent DE. It's really not that hard if you ask for help on the archlinux forum: bbs.archlinux.org
You'd be very satisfied with the end result once you get it installed (installing arch really goes fast..). It boots incredibly fast, runs fast , is easy to upgrade , ... Just be sure to download the 0.7.1 pre iso(
ftp://ftp.belnet.be/packages/archlinux/0.7.1/iso/i686/ ) if you try it, there have been big changes since 0.7.0. Well anyway, I don't want to persuade you, but if you need help to install and configure arch. Just ask, you'll get answers and learn.
Really, arch linux saves me plenty of time because it's so simple. I found no other distro where it's so easy to install the binary ati drivers for example, or the mplayer and flash plugin for firefox.
Slackware ditto? Slackware was the first linux I got installed because it's so easy, did you select KDE or Gnome to install in the installer? That's all that should be done to install a DE in slackware. I bet xfce can also be chosen in the installer, but I don't know for sure.
What kind of internet connection do you use? As I could point out how to get you online in the console (or during install). It's really not that hard.
Just ask here if you need help about installing anything. With such help you can install any linux distro. Just ask.