lenovo has 2 brands: the Thinkpads (which are the classic, IBM style laptops) and the Ideapads (that are aimed more for consumers).
Both are high quality, but the Thinkpads have some nicer software features and look a lot nicer (but come at a higher price).
If you're a serious gamer, my advice is always to go with a desktop. Laptop gaming never ends well. However, for moderate gaming, the Ideapad Y series is pretty good.
WOW and STO are fairly low-intensive when it comes to graphics, so almost anything should be fine. If you want a more powerful machine, I'd suggest the Thinkpad T series. I prefer my laptops to be very portable (as I have a desktop only for gaming and a lab computer only for running code), so I use the Thinkpad X series.
With the X, I'm able to get OK framerates in Minecraft and LoL, but WOW may be a bit too much, especially if you like to play for several hours at a time.
@Tom
What does your roommate use his computer for? But, basically, my suggestion would be the same: X for portability, T for power, Y if he really wants to game and for some reason can't have a desktop.