Hmmm. I know that you've probably googled and found these sites:
But, here they are again anyway. Debian on a laptop is cool because apt-get gives you access to a wild array of software that is for the most part pre-configured and ready to go once you install it. That said, I would certainly be using Debian-unstable as that software is a bit more....cutting edge. Just my opinion.
As far as "putting your laptop to sleep" goes, my opinion is that it is an overrated feature. That said, there is a kernel patch called softwaresuspend2 that will do what you want. It's very beta-class, works erratically on some distros, and the patch itself forces some software (like VMware) to break or not install. The state of linux on laptops, in general, is mediocre at best. Wireless drivers are subpar with poor coverage of the number of devices available, there is no good network profile switcher available, acpi power management is very much a work in progress, and you generally have to put a lot of elbow grease in to make everything work right. THESE ARE NOT GRIPES. They are just statements of fact. The various drivers and programs are coming along, but there's still a ways to go. If you like Debian, you may want to drop some cash on Linspire's Laptop Edition. I'm not a huge Linspire fan, but enough of my hardware worked when I tried it that it gave me pause. It's the sticky-icky-ickiest of the GUI distros, but software suspend does work, as well as power profiles, network switching and such. Also, I've heard good stuff about Ubuntu. Both are Debians, so you have access to all the software.
I'm a glutton for punishment. I use Slackware and configure everything by hand from the ground up. Takes me about a week, but the results are a system that does EXACTLY what I want.
Try some packages like:
1. synaptics - for your touchpad
2. laptop-mode-tools - for prolonged battery life and CPU frequency control
3. software suspend 2 - for your sleep function
4. acpi - for power management and a variety of other functions. APM is the older version of the same thing.
5. kernel-level cpu frequency governors - these will control your CPU frequency according to a particular profile like "ondemand" which throttles the frequency to it's lowest point and increases it according to load percentage.