What notebook do you think I should get?

I have a question. What notebook do you think I should get? I am in the OA which is a Boy Scout Organization. I have to attend council meeting at various different places such as at Camp Wolfeboro where their is limited power and no internet. They recommend that I try to get a notebook. I am on a pretty tight budget though. I need to be able to run multiple apps at a time such as Office 07 PowerPoint along with Firefox and Office 07 Word. I do have experience with computers (I recently built a computer for my room) so upgrading the Memory and HDD won't be a problem. I'd say I cannot spend any more than $800 at most. What do you think is the cheapest computer that still retains construction quality and warranty but I could afford? A specific Notebook please!! Thanks for the Help.

Budget: No more than $800 but the cheaper the better.

Size: I have no definite size but I was thinking a 15.4-15.6 inch for portability and cost

Battery Life: Need a long battery life because I may be away from a power outlet for a long time. At least 5 hours

Games: Not really going to play games I have a gaming computer at home and this isn't for that. Maybe Portal or something when I get bored in a meeting or something.

Tasks: I want to do general tasks and have multiple windows open at a time Such a 3 Word 07, Firefox with 4 tabs, 1 PowerPoint, and Thunderbird at the same time.

Capacity: I can mirror the built in hard drive to get a bigger one. I will use 200Gb Roughly

Preferred Site: None in particular just want to be able to recognize the name.

Length of Use: I will probable want to use it for 3-4 years.

Brand: I have had some bad experiences with HP but otherwise if it fits what i want its good.

Country: I live in the Good Old USA