I've just purchased a Toshiba Satellite P30 (17") and I'll receive it in 12-15 days. (That's what toshiba direct says anyway)
Well; first of all ; back up all of your important information to CDs. (Hopefully yours has a cdw)
I would first say to try Knoppix; if everything is quite working with it ; you can use any debian-based distro. Mepis and Ubuntu are perhaps easiest to install ; but I've heard debian is quite good on laptops.
On the other hand, also d/l a live suse if knoppix doesn't work quite right ; I know that suse is working quite nice on my mom's sony vaio laptop. (I installed it, she's very happy with it and never screwed it up.)
If not; also download Slax which is a live version of slackware. Slackware is customizable towards anything if you know what you're doing.
But at the end; you might be most happy with debian based distros or debian ; since you can download any program you want from their libraries using apt-get. (Synaptic in your experience I assume)
Have fun !
I'll first try to install gentoo and see if it works; if not I'll probably go for debian as well.