Depends on the Distro.
It also depends on what hardware you are talking about.
A lot of distros have nice installers that take care of troublesome things like installing and configuring driver modules for various components. SuSE for example has a tool called YAST2. Also, there is SAX2 for video configuration.
Some distros are debian package distros,... like Debian (duh). Others are RedHat Package Manager (RPM) distros,... like RedHat (again, duh), SuSE, Mandrake, Fedora, etc.
Apt-get can also be used to install drivers and applications. It is a command that searches known databases for the latest version of a program, and together with its dependecies, installs it on your system. It's a very handy way of installing programs and is commonly used in Slackware.
Keep in mind that anything you can install using nice tools can also be installed using a command line. RPMs, for example, can be installed using the rpm command. Syntax of these commands is very important, and you have to know what you are doing.
Drivers can also be compiled manually from "tar-balls" that you download. You "untar" the file to a directory (much like unzipping), and then install with the make and install commands... It requires you to know a little bit about Linux to do this (Hence, things like RPMs, Debian packages, and the apt-get utility).
Once a driver is installed, you may have to configure the system to use it. With video, for example, you need to edit the X86Config or Xorg configuration files. Many distros have tools that do this for you (SAX2 for SuSE, HardDrake for Mandrake, etc.). You may also have to make the system use the particular module... using modprobe, insmod and lsmod,... Again, most well developed distros have tools to do this stuff.
Drivers can also be compiled into the kernel. The user can use the driver software together with the kernel source-code to create a custom kernel made specifically for that machine. The advantage is that the system will run quicker with less mess, after the custom kernel is properly compiled and installed.
So,... you can see that Linux is quite versatile, can be complex, but can also be easy to use...