Slackware 10.2 is the most recent release. Slackware current begins where 10.2 ends. Packages are gradually upgraded and eventually released as the next version. 11.0. Generally you would install 10.2 and then upgrade to current if you want.
As far as partitions, you only need root and swap, but might want to have /home or anything else you might need to preserve. /var and /temp are sometimes recommended if you're running a server.