Personally I wouldn't touch Packard Bell, or Acer with a 50 foot barge pole... mind you they are still both 100x better choices than Compaq, Lenovo, or Dell.
I'd be looking to see what's on offer through Alienware, Toshiba, and MSI... though all of those brands probably don't manufacture something in the price range you are looking for.
The Packard Bell sounds like it has some good features for the price, but I'd be concered about the quality of parts, especially for what you are getting for the price... you get what you pay for when it comes to anything, but it rings more true to home when talking about computers.
In all honesty, if you can squeeze the budget a little more, you'd be better off pushing up to the �650-700 mark as you would get an infinately better machine for the extra.
Also 2.3 hours battery life is about average these days, but it depends on what you buy. My MSI EX600 notebook has a battery life of up to 4 hours (core2 2.2ghz, 4gb, 250gb, GeForce 8400) and I bought that over a year ago. Of course this soley depends on turning off things like wireless, and dimming the screen so low you can hardly see it unless it's pitch black in the room. A "realistic" operating time on battery is between 1.5-2.0 hours.
Also, keep in mind, the larger the screen gets, the less of a "laptop" it becomes and more of a "desktop" you end up with. 17" screens on laptops are generally a regreted purchase from my experience when dealing with customers... they always tell me later on that they wish they didn't get one so big, because the laptop is gargantuan and it weighs more... plus things like carry bags cost twice the price of a 15.4".
I guess, as long as you know all of this... you can make an informed descision. All of what I have said, can be summed up as an "opinion", or you can put it down to the last 13 years of experience I have had dealing with this stuff just about everyday. Either way... if you buy a Compaq (officially the WORST brand EVER) I will have to fly over there and strangle you in person!