1 and 2. Opinionated question. I think Slackware is the best, but that's just me. There are lots of differences between distros.
3. Yes, it does.
4. When you install whatever distro of Linux you choose, it will let you set up either LILO or GRUB, depending on the distro. These generate a menu at startup letting you pick between Windows and Linux.
5.
http://tldp.org, http://linux.org