Laptop

One thing to keep in mind: a lower priced computer will often have a shorter useful life span. If you want the notebook computer to last 5 or more years you'll need to at least buy in the mid-range tier. Certain entry level notebooks will not be equipped well enough to just run Illustrator in a basic manner.

Current operating systems (Windows or Mac OSX) have their own resource demands, which can be somewhat serious. Just for a general purpose computer that can play videos in HD and do office productivity work a system with 8GB of RAM may struggle. Graphics applications need even more RAM. I would recommend at least 16GB of RAM at the bare minimum, if not go up to 32GB. I'm using a system with 64GB or RAM, but it is a fairly high end machine.

Avoid computers that use integrated graphics chips. Most low cost notebooks and even some mid range models have integrated graphics chips rather than a true graphics board. Many thin and light "ultra portable" notebooks will have limited graphics capability as a trade off for having really long battery life. A dedicated graphics board will have its own on-board GDDR RAM and generally operate much faster. It's not necessary to buy a top of the line gaming computer or workstation. There are plenty of mid-range graphics boards. A notebook with a dedicated graphics board from NVidia or AMD will allow you to have GPU-accelerated features in Illustrator such as animated zoom. A good dedicated graphics board is a must to use the 3D features in Illustrator.

Vector-based drawing applications like Adobe Illustrator lean pretty heavy on the computer's CPU. A Windows notebook with a Core i5 CPU will work better than one with a low cost i3 CPU. Likewise a Core i7 CPU will beat i5 performance handily.

One more thing: pay attention to what kinds of ports that are included on the notebook. Consider the different devices you might want to physically connect to the notebook. That could be one or more external monitors, portable hard discs, external DVD/CD-RW drive, USB memory sticks and all sorts of other things. Some notebooks will include multiple USB ports, HDMI, Display Port, Ethernet and more on the back or sides of the notebook. Other notebook models offer a minimal number of ports, like maybe only a couple Thunderbolt/USB-4 ports. Those kinds of notebooks will force someone to buy an external "docking station" with lots of the ports I previously mentioned. Some docking stations, especially the Thunderbolt ones, can get really pricey (like well over $300). 

Also a great opportunity is to opt for a refurbished laptop. That way you get acces to a stronger machine for less money and it will still have a warranty.

Which country are you in? Mac or Windows? What's your budget range? "Arm and a leg" means different things to everyone.

What size screen do you prefer? Do you use an external monitor?

Do you buy online or instore? I never buy instore. I find online is invariably better.

It would probably be more productive if you just picked one that's okay within your budget and a possible alternative and then asked whether that's good enough. If you're strictly talking AI, you'll get away with a mid-range i5 processor, but for that 3D stuff it will require a dedicated NVidia or AMD graphics processor. And of copurse deck it out with as much RAM as it can handle. Most cheaper laptops will only have 8 GB, but 16 GB is really a lot better.

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