Generally, Synaptic is easier than most windows installers (IMO, although it appears IYO as well), as long as you know what package it is that you're looking for (or at least have some good idea).
Synaptic presents a list of 27,712 packages to me (Deb Squeeze), a large percentage of those are software which I don't know anything about -- and the descriptions in Synaptic are very frequently not enough to tell me something about them. (Although a quick Google usually does) Some of them -- like kernels and libraries -- are utterly cryptic unless you already know something about them.
Windows solves that problem through advertising. Microsoft, Adobe, Nero, Roxio -- names that are recognizable quickly, because they're advertised so much. The result is that users of windows, even when they themselves don't know what they want, often know the piece of software that does it.
KDE has an interesting package manager available, which is highly simplified and shows only what users might classify as "applications", in categories end users would easily comprehend. If I were a user of the "end user" variety, I would find that helpful, because knowing to install the package called "kopete" or "pidgin" to get instant messaging is not as easy as seeing "Instant Messaging" in the categories and then picking one (or even having a default picked). This certainly goes a long way to solving the problem as well (if such a tactic is widely adopted, that is).
So, I guess it depends on what you're looking at when you consider installation easy. The actual act of installation, or the act of finding which packages it is that you want to install -- because the first is generally the roadblock for users, not as often the second. And the open source tendency to use acronyms and puns doesn't help that matter, fun though they may be.
(For the record, I did install Ubuntu on my mother's computer; and it's worked out fine. In fact, finding packages seems to be the only difficulty she has on a daily basis.)