Asus laptops are generally pretty powerful laptops for the price you pay (I have one, and it's been a good quality laptop). Maybe something like the ASUS G51VX? The only thing it doesn't seem to fit with your description is that it's a flashy looking laptop, and it might be a little higher priced than your budget. It should at least give you a good starting point though.
Here are some points you'll want to consider in your search:
- You'll want to have a dedicated card if you're planning on playing games.
- For a higher performing laptop (especially with a 7200RPM drive), 2 hours is probably the most you'll get out of a battery.
- Newegg is a good place to search and get an idea of what you're looking at. You can use the Power Search function to really get good search results, then take those results to whatever site you plan on purchasing from.