First of all, instead of considering buying a new laptop, you should try to get a Laptop Cooler, it should cool the laptop so that the fan is not that loud or you should use the laptop inside a AC room (or outside when its snowing

). Laptop Coolers are a great way to help you keep your laptop cool, and it also shown to increase Laptop life. You should get a laptop cooler from Logitech, Xpad or Antech, these are trusted companies and trusy me, their products work
Also, rather than buying a different laptop or buy a laptop cooler you can make your current laptop more silent by some simple tricks. Try installing a program called SpeedFan and adjust the settings so that it can control your fan's speed but don't put it too high (or your battery life will die) and don't put it too low (it can fry the motherboard!) the default settings work fine.
There is also the cheap method (and very effective method) of putting a small bit of tap over the air vent on your laptop. It is proven to work (I actual tried it) and it doesn't overheat your laptop, it just makes it slightly hotter but the humming and hissing sounds disappear. Here's how you do it:
Take a small bit of of tape (duct tape, scotch, yellow tape, etc.) and any other tape (except packaging tape

). Tape it to the side of the air vent. Not to much to the side though. Make sure that there are no holes in the tape. The circulation of air should be restricted away from the tape. It should make the laptop much quieter.
You should also try putting the 'Power Plan' of your Laptop to 'Power Saver'. It doesn't affect the Laptop performance that much. You can do it by clicking on the Plug and Battery button on the right-bottom side and going to 'More Power Options'. Then in the bottom choose 'Power Saver'.
IF all else fails and you WANT A NEW LAPTOP (

) than I would suggest buying the dell e1705, sony sz, dell e1505 Sony Pcg nvr , toshiba libretto,etc. I just ask the guys at the computer store and you get advice from them, usually the A8J's are the most silent of the rest. With the A8J's I could play a hardcore MMO-RPG game and not even feel a vibration of the laptop (except the speakers, of course.)
Or you can try turning the FAN OFF! HAHA... Just kidding !