You might try replacing your AC adapter.
If you're buying a new laptop, I would only recommend getting a getting a good video card unless you plan on playing alot of 3d games.
Processor-wise, any dual core processor is probably good enough. I would want at least 2 GB of RAM. Granted, it's easy to upgrade, but why use a computer that has less than 2 GB of RAM?
It really depends on what you're doing without it. If you're just using the Internet and writing documents, it doesn't really matter what you get.
If you plan on storing alot of data, whether it's games, movies, or whatever, you should probably get a fairly large hard drive. Otherwise, try to get one that's fast, even if it's relatively small. Don't get a flash drive; they're too expensive and are too small.
Unless you plan to watch high def movies or burn cds/dvds, you should get the cheapest DVD drive available from wherever you're buying the laptop.