Hi, it depends on what specifically you want (what operations) to be able to do on your laptop. If you'd like to game then it's much cheaper to make your own desktop with superior specs. However, if like me you're set on getting a laptop that can game then I'd recommend against Alienware as you're paying for the brand rather than a valued good (although they are great machines). A common problem with 'gaming' laptops is that they're too heavy to carry around so it's basically like having a small desktop (another reason to build a custom PC).
If you're designing a gaming laptop then the most important things are:
1) CPU (processor)- quad core is best and the faster the better- 2.5GHz+
2) Graphics card- dedicated
3) RAM- 8GB+ would be great…
For the Lenovo you've linked on Amazon, it looks pretty good with a great CPU at 2.6GHz. However it's only a dual core, for multitasking having a quad core is advantageous. The more cores (+threads) = more tasks can be run simultaneously. Also the graphics card is integrated so will have limited graphics capabilities on games (no way it'll handle new games in greater than medium).
The minimum specs needed for League of Legends are:
Minimum System Requirements
* 2 GHz processor
* 1 GB RAM
* 750 MB available hard disk space
* Shader version 2.0 capable video card
* DirectX 9.0 capable video card
* Windows XP SP2, Windows Vista SP1, or Windows 7
Therefore the first laptop meets the CPU, RAM, HHD, but possibly not the graphics/video card (Amazon doesn't specify what card it is).
For general work it looks pretty good, however I would try to find a laptop with a quad core if you will want to be doing lots at once.
If you'd like more detail on this then please don't hesitate to ask!
