While I'm not familiar with laptops in general (they're such a moving target), I can suggest some guidelines:
1. The screen. You want 1080p+, IPS, with good contrast and color reproduction. It has to be flexible enough to be calibrated to your needs.
2. The CPU. You want a quad-core i7 with hyperthreading- be specific here. In the mobile arena, Intel's 'i7' moniker can mean anything.
3. RAM. The laptop should preferably have four slots and be able to accommodate 16GB, if not more, depending on your budget.
4. Storage. A decent sized SSD along with a larger 7200RPM drive would be ideal, but going for something like a hybrid drive or using an mSATA SSD for caching would probably be a good compromise.
Less important but definitely nice to have:
1. Solid and durable chassis.
2. Quality keyboard with a good layout and a quality touchpad.
3. Good speakers.
I don't think having a discrete GPU would help you much, except in the case of drivers; someone else will have to help you there, but I do know Nvidia's Optimus technology seems to be preferable for ease of use and battery consumption. The HD3000 is more than powerful enough, and you may find it's Quicksync function to be useful.
A price, size, and weight range would also be helpful, as well as any specific dislikes.
Canon 6D|24-105/4L IS USM|70-300/4-5.6 IS USM|40/2.8 STM|50/1.4 USM|85/1.8 USM|Samyang/Bower 14/2.8 Full-Manual Rectilinear Wide-angle|24/2.8 IS USM|
Canon EOS-M|11-22/4-5.6 IS STM|22/2 STM|EF-M 18-55/3.5-5.6 IS STM|