"I do a lot of encoding and burning, surfing and downloading but not gaming."
Surfing and downloading doesn't take a lot of processing power or memory but encoding does (if you want it not to be a long drawn out chore). So look for the best processor you can get with your budget, probably an Intel i5 or if possible an Intel i7. Also go for a 64-bit OS to allow you to use more memory than the 4GB a 32-bit OS is limited to. With all that video work, a large Hard drive capacity would be useful or get yourself a large external drive at the same time. If you have a large flat-screen TV look for outputs that will allow you to connect your laptop to your TV to view your finished projects in detail.