1. Loads of choice in that price range.
2. 15.4 inch one of most common sizes... if you don't need to carry it around suggest looking at 17 inch.
3. Screen resolution isn't an issue. You can adjust text size etc in Vista (and presumably W7) by altering DPI (Dots per inch) without lowering resolution as that makes things bigger but more blurred.
4. How portable... see 2
5. They all give that, some like the new Acer timelines give 8 hours
6. Gaming (for high quality graphics/fast action at high frame rates) requires a high performance machine... otherwise not such an issue.
7. Anything in your price range will all do that.
8. HDD size. Unless you store DVD's (moving pictures as opposed to stills) you don't need huge amounts. Anything in your price range will be OK >160gb
9. As your in $ dunno...
10. Look after it... it should last. Open laptops carefully, not by grabbing a corner and yanking it open... hinges can be a problem on some models if your careless... otherwise no problem.
11. Acer... because I have one 3 years now and it's been fantastic. As with anything you can be lucky and unlucky.