Do a full install. Don't bother with kdei, that is the internationalization package for KDE. I never need any of the international settings. Note: I am one of those crazy Americans. You may actually need the internalization settings if you're not! I also get rid of lprng. I use CUPS. If you have trouble with CUPS, try making sure that the lprng package is removed and re-install the CUPS package. I also start up everything except rc.atalk, rc.bind, rc.lprng, rc.pcmcia, and rc.mysqld. I go about securing my box later. I just find that I have no use for any of these things. YMMV. A great website to check out for some tips on installing Slackware is here.
I know that a lot of people get hung up on partitioning. My recommendation is that you go with the path of least resistance. That means that you are only gonna need two partitions for your install, a root partition and a swap partition. There are a lot better partitioning schemes out there, but this one will work. Just make a swap partition twice the size of your RAM and another partition that takes up whatever free space you have. This is simple and doesn't require a lot of thought. When you feel more comfortable with Slackware and Linux in general, you will probably want to make separate partitions for /home, /var, and /tmp to make your box more secure (stable) and make upgrading easier. When I started out, though, partitioning was confusing. If you run only a root and a swap partition, you will get a feel for how big to make each of your partitions in the future.
I was scared the first time I installed Slackware. I kept thinking I was going to screw my perfectly good Windows installation up. I decided to boot from a floppy. Finally, I decided to install lilo on the MBR. Lo and behold, it worked great. Made booting up a lot smoother, too. Don't be scared to go with the MBR. Just make sure that you make a boot disk when the installer asks if you want to. Saved my butt more than a few times.