Mmmmmm, definetly, don't put Mandrake....(I hate it...) I have a RH9 and works pretty good with me, also because i have quite brand new PC (8 months old).
I think any "new" distro will be quite slow on that laptop anyways, so it's up to you.... I suggest you go to the main distro's website and choose from there. Most of the times is just a matter of likes and dislikes.
Easy to install and full of shit distro's: mandrake, redhat, suse
Hard to install and you only put what you really want: Debian, Gentoo
Never seen a Slackware, so i don't know where to put it
Hope it helps