Because ther are laptops with better specs than the PS3, they can generally perform better than a PS3 or Xbox. One thing to consider is that PS3 and Xbox 360 games are not 1080p; at to the best of my knowledge. They are generally 720p resolution which can be upscaled to 1080p. Doing so will cause a small drop in graphics quality, but you don't hear too many console gamers complaining because they can't compare native vs. non-native resolution on a HDTV.
A powerful laptop on the other can allow you to play a game at 1080p (1920 x 1080) though. To get better performance, you can always do what consoles do which is to set the game to a lower resolution, then stretch it to fill the screen.
Be forewarned that there are console games that have been ported over to the PC which were not properly optimized. GTA 4 is an example. The PC version has high requirements (like a quad core CPU) because of poor coding during the porting development. Needless to say, GTA 4 is more enjoyable on a console.
exactly i was going to say, jaguarskx has already explained. But if you names of those monster laptops, you can get sager, asus, msi, alienware. Just make sure that you buy the one with 5870 or gtx460 or above and i7 and you will be able to play most games(80% or more) on 1920x1080 or 1600x900.