There are many choices available. Before you start comparing, it is worthwhile to consider what features are most important for you:
A) how big a screen would you like?
B) how light does it need to be? (A and B are often in conflict) Are you going to carry it around a lot, or just leave it sitting on a table?
C) how fast does it need to be?
D) do you need discrete graphics? (usually more expensive, but useful for games)
E) do you have a preference for the mouse-replacement (I can't use touchpads very effectively so I am pretty much limited to Lenovos). Getting an external mouse can be an option.
F) is battery life important to you? Many of the cheaper laptops use desktop processors that suck a lot more power. Also larger batteries weigh more than lighter ones.
G) external connections -- are you going to want to hook up lots of things to it (such as external harddrives, televisions/monitors, a mouse, headset, projectors etc). Some laptops don't have very many connections. Check in particular for the number of USB ports and whether the video is VGA/HDMI or one of these other newer ports.
H) Do you need bluetooth? (convenient for transferring files between laptops, hooking up a headset or sharing your internet connection from your cell phone)
Once you have answered these questions, scan the available laptops for ones that meet your requirements.
You will probably find that the laptop you want is much more expensive than you had hoped to pay. In this case, go back to the questions above and see where you are willing to compromise.
Hope this helps.