It really depends on how much money you have. For example, laptops can do content creation "well", especially if were talking about 720p and 1080p, just look at the RAZER BLADE STEALTH starting at $999. That being said, rendering video is (95% of the time) a CPU intensive task. Cores are the most important factor for rendering video (the more cores the better) Intel i5 is the best value processor, and if you're thinking of something more expensive, don't unless you're considering 4k rendering. To which case you'll find i7's and Xeons to be sorta similar, you might be able to find a cheaper Comparable Xeon vs. a Comparable i7 (But if this is going to be a gaming machine as well, avoid the Xeon and get the i7). Also, an additional hard drive where you will be /rending/ to reduces bottlenecks and improves the life of your system (just make sure the second drive isn't slower than your primary drive) This is especially true of Adobe Premier where Adobe themselves highly recommend a second drive to render to.
So in short, I too recommend an i5 (but it doesn't have to be the latest/greatest) and think about having a second hard drive to render your videos to otherwise you'll be bottle-necking yourself and shortening the life of your main drive.
I don't know what processor your laptop has but if you have a quad core (especially an intel quad core) consider rendering to an external hard drive that is as fast or faster than your current hard drive (also upgrading your laptop's hard drive wouldn't hurt either) before making the leap. In general rendering in HD takes a long time anyways but if you're rendering 30 minutes in 1080p for 18+ hours....yeah that's a problem lol