Go to a circuit city or comp usa.
Look at 15.4" laptops
Looks at 17" laptops
Decide, do you want screen realestate, or do you want shear CPU muscle?
They both use the same graphics card. If your games are CPU limited and gaming is more important than screen size go with the Acer.
Also there is the question of $$$$$
Using the Delf 25% and Educacational purchase program (see notebookforums.com for details) you can get a $2200 Inspiron for around $1600. As far as I know a $2200 acer is going to cost you $2200.
Be aware some users are reporting issues with the high res screen on the 9200.