Have a look at http://pricespy.co.nz/ I'm looking at laptops at the moment, some have DDR2 memory, others have DDR3. If you upgrade later, there can be quite a difference in cost. However, most at that price will sell with 4GB, so it's probably not going to be an issue for you.
Something to consider: if the hard drive fails, can you get a windows partition back without having to buy Windows again? My last Toshiba (bought 2 years ago) has a windows partition, but also allows you to create a DVD which can convert a new drive back to as bought with laptop condition. This is a regular topic here, people who have lost their Windows partition and no way of getting it back.
I'd suggest that you don't buy a laptop without seeing it in a store, as sometimes you'll notice something you don't like. Finally, after a couple of years, a white keyboard shows off less grime than a black one.
Couple of little things: a wheel volume control is much easier to use than using the keys. Also, if the power socket is on the same side as the vent, you can easily put the laptop on its side while doing things around the house. If they aren't, it's more fiddly. (These wouldn't be high on the priority list).