When do you go compare, you will want to ensure that your graphics card is able to upgraded. So you DO NOT want an integrated graphics card, if it is intergrated...let me say it blunt, it is crap and not meant for gaming. Dedicated graphics card is a must and will save you costly replacements in the coming years. You will want to get as much ram as possible 2GB is ideal (minimum), 4 GB is better!
Alienware is top for gaming
Alienware Computers - Custom-Built Gaming Desktops and Notebooks Take a look at their laptops. Dell XPS is also quite good, but once all the upgrades you require it will cost you a small fortune. You will want to stay away from buying it from a bestbuy, futureshop, staples, etc. Do not go to box stores, I suggest going to an actual computer store. The best kind will build one with you. I would also make sure to take note of the specs that WaW and COD4 require, and ensure that the laptop has those minimum specifications.
Best Gaming Laptop Of 2008 | Geek With Laptop
Top 5 Gaming Laptops - Computer Shopper
You will notice that these are all quite expensive, but the laptops are the best on the market and will hold up to some future games. Every laptop you look at, ensure you are looking at the graphics card and the motherboard. Feel free to post the specs here to get a second opinion. Remember DEDICATED graphics is a must.
As well, any reason why you are wanting a laptop over a desktop? You can get a far better desktop for a quarter of the cost.
If you have more questions, just ask!