firstly u have to keep in mind of a very performing laptop model:normally ACER is the best. personally i will tell you that: i understand there might be some budget constraint but u will have to use it for a lifetime...quality is better than quantity...u may refer to these points of view:
1. Comfort
Inspect the keyboard layout of the notebook computer. Make sure the layout is the same as the current keyboard that you have been using all this while. Look out especially for the keys "@", "/", "\", "%", [Home], [End], [Ins] and [Del]. If they are not at the "usual" places, you would need to face a learning curve after you have bought the notebook computer.
Try to type on the keyboard and see if the keys are too wide or too close together. If they are too wide or too narrow, it could put a strain on your hands if you type a lot using the keyboard.
2. Processor Speed
Unless you are a super power user, it actually doesn't matter whether or not you get the latest available processor. Processing speed is now so fast that the human brain cannot even imagine the difference between a 1.4GHz processor and a 1.7GHz processor. When selecting the processor, choose a recent model and not the latest model unless your budget fits the bill. Otherwise, it's alright to choose a slightly slower processor as you would not feel a visible difference in the processing speed. Spend your money on more RAM and storage space.
3. RAM or Computer Memory
This is one area you don't want to compromise on. If you are using Windows XP Home, 512mb of RAM is a good minimum to start with. If you are using Windows XP Pro, 768mb or 1GB of RAM is recommended for optimal performance. Beyond that, let your budget do the talking.
4. Display Memory
Most entry-level computers share part of the RAM for video display memory, which also explains why entry-level notebooks are cheaper in a certain way. This also means your memory performance is somewhat compromised and you won't have as much RAM as you want for your notebook computer. For example, if your notebook has 256mb of RAM, and the computer specifications for video display states 64mb of shared memory, it means that you only have 192mb of RAM available for the operating system to use. Generally, this translates to a slower performing notebook computer.
The high performance computers usually have a separate display memory card built-in that gives the high performance, while the highly mobile computers may also deploy a shared memory strategy for display memory, similar to entry-level computers, due to the need to keep the form factor small.
If you budget allows, go for a independent display memory of at least 128mb.
5. Hard Drive Storage
The cost of hard drive storage have come down quite dramatically these days. And 60GB/80GB would be the minimum norm for most computers. Plan to have at least two partitions ( C: drive & D: drive ) for your harddrive. Store only programs on your C: drive and all your data on your D: drive.