1. 802.11n probably won't become truly widespread for another few years. The n out right now is actually a draft version, but probably isn't going to vary much from the final. If you can find a card that is 802.11n/g/b and is not too much more than a similar 802.11g/b, I would get it. But it isn't too important.
2. 4200 RPM, 3600 RPM and lower are fairly slow by todays standards and you will notice things working slower, especially with larger files. 5400 RPM is more or less the standard, and it is a good compromise between speed and price. 7200 RPM HDD are available but are more expensive for the amount of space you will get. Just think, in a number of years we will probably saying goodbye to HDD in general and ushering in more solid state drives.
3. Yup, the next round of Intel Core 2 processors are being released at the end of December and beginning of January, so if you can wait, prices will slowly start to drop. 2 GB of RAM is a good choice, especially if you are choosing to run Vista. Other things to look out for... since you are using it at home and school make sure it is a mobile processor, a smaller screen (probably don't need 17 or 19 inches), investigate the batery life (the number they list is the absolute ideal, expect lower), and watch the weight (remember you have to carry it around). Since you are not gaming, I cannot really think of anything else, since an integrated sound and video card should work out fine.