It would probably be better to get a desktop computer now and a laptop later.  Desktop computers are cheaper and easier to upgrade.  I don't know if price is a factor for you or not, but most people don't use a laptop to play games.  You can...but you normally get better performance from a desktop because you can get more powerful video cards and stuff in there without the risk of overheating as much of a threat. 

Do you plan on taking it places or just having it as a permanent desktop replacement?  How long will it be before you can get another computer?  Laptops are meant to be durable, but they don't last as long compared to desktop computers. 

What I would recommend:
Intel Core 2 Duo processor
250GB Hard drive
Video Card that supports DirectX 10 with at least a 256MB cache
DVD R/RW
2GB of RAM

If you get a desktop computer, you also might want to make sure it has DVI out and a monitor that supports DVI.  At least a 1280x1024 resolution as well.