Hard to define one particular distro that would be perfect for your laptop. I would say that distro doesn't matter, the most important [as you probably know] is linux kernel because it "controls" everything.
Different distros has a lot of different tools to offer and it is up to you which ones you feel the most comfortable with. I mean for example Mandrake or Fedora come with a great set of GUI tools that make you feel like you are still using Windows - everything is automated, it detects your hardware without any problems and stuff like that, whereas Slackware for example is just a plain and simple distribution that isn't stuffed with various GUI tools and stuff ... you do most of things by editing config files ... it may sometimes be tiring but also very rewarding and causes you to think a little more while doing something in your system not just clicking "NEXT" ... the more time you spend on something, the harder you think how to solve some kind of a problem the faster you learn and using "hardcore distros" [Slackware is often called that way] begins to be as quick and easy as distros loaded with GUI tools. So ... I don't want you to get me in a wrong way. It is your choice which distro you will be using.
I have a Dell Inspiron 8200 laptop and successfully use Slackware on this machine, before that I was using Dell Inspiron 5000 and also didn't have any problems with it. I've been using Slack from the very beginning when I started to take linux as a serious OS and the saying "Once you get slack, you'll never go back" came true
You may find a lot of useful information here:
http://www.linux-on-laptops.com/dell.html
