Recommend a laptop for a grad student who knows nothing

You really can't go wrong with a MacBook Air. It's an unbelievable combination of quality, performance, and size/weight. I honestly think that if you can swing the price, it's worth it for pretty much any application. AppleCare is probably worth it for a daily-commuter type of computer -- if you're like me and your laptop is docked 90% of the time, I wouldn't buy it. That said, zug is right too. You can get a $300 Sony/Vaio/Dell/whatever laptop and not think too hard about it until it breaks or gets too slow in a few years.

Fullsize keyboard is important. When you're at home, use a desktop keyboard. When you're laboring at a paper, having to contort your hands to type on a small keyboard will detract from the already unpleasant aspects of the whole paper-writing experience. (It's also nice to have the keypad when you can.) Don't get HP-- they do many things well, but in my experience, laptops are not one of them. Dell can be good, as can Toshiba and especially Lenovo. If I was buying tomorrow, I'd go with a Lenovo; not entirely sure I'd get a touchscreen version, but I'm not sure I wouldn't... All that said, I run windows (bootcamp) on a 2009 work Macbook Pro, and I'm happy with the hardware. In terms of bang/buck, the laptop sweet spot seems to be around $750-850, but you'll end up at $1000 with accessories (max out the RAM if you can, and get a spare power supply). Consider a port-extender, but that can be bought later.

Congrats on passing! Last year to celebrate my passing of my comps, I bought myself an Asus UX31A--it is an "ultrabook," powerful and light. It hits your main needs. I am a crazy multi-tasker and I have run Stata (hefty national data sets, too) with Excel, Word, OneNote, a million Firefox tabs, Spotify and other programs simultaneously with no problem. The screen is a good size to have all the windows up. I am currently writing my dissertation so I can tell you that it has been a comfortable keyboard to type on. I also just quickly Googled it and it is on sale via Amazon for roughly $850. Nice deal for a good, new machine. I never buy used so can't help you there. I use laptops for an average of 4 years and donate.

If I were you, I'd get a 13" MacBook Pro. I still use my 2009 model on a daily basis. Even after dropping it / treading on it regularly. It's so well built. The new retina displays look amazing as well. However - the best reason for getting a mac, is every couple of years you can upgrade the OS for $29; you get a ton of new features, and it's normally leaner and quicker every time. No worrying about Windows 8 style debacles. Also using your own mac with admin privileges will be a completely different experience.

I don't know Windows machines, so I can't make a recommendation on Mac vs. Windows, but I can say a few things about Mac notebooks. In my experience, the current MacBook line is fairly well made and tough. If you do get a new Mac, I do recommend AppleCare, though, for the 3-year warranty. The video on my old MacBook Air failed about 2-1/2 years after I got it, and Apple ended up replacing the machine with a recent refurbished model with twice the SSD storage and a much faster processor. The keyboard on the MacBook Air is full-sized, even the 11" model. On the other hand, the 11" screen is a little small for reading article PDFs. The 13" is a good compromise between portability and screen size. The Retina Display model is steep for a grad student, but the high resolution does make PDFs somewhat easier on the eyes (maybe more of an issue when you're in your 40s, like me). The non-Retina model is a little heavier (but has an optical drive) but not too heavy, and it's much less expensive. If your university has an Apple store in its bookstore, you can probably benefit from both the MA tax holiday and the small discount Apple gives to higher ed customers (last I checked, it was $50 off the retail price on laptops).

Have you checked with whether your university has an educational discount for Windows laptops? Most universities do, usually for laptops from Dell, HP, or Lenovo. They'll also have arranged for discounted warranty. I really recommend getting the warranty in the case of laptops. If your home computer is running windows, I would recommend getting a Windows laptop just to keep your computing environment consistent, including not having to have two versions of the same software (and I'm saying this as a Mac user with a full range of Apple products who nevertheless alternates between Windows and Macs during the course of the workday). Instead of looking for a laptop that will last for four or more years, I would get a new laptop around the time you go on the job market, just so you won't have to worry about the machine dying on you in the midst of a job talk. By then, what you want from a laptop might have changed, too. For example, a lighter machine may be more important once you start having to lug it through airports on your way to and from campus visits.

The macbook air 11" and 13" have fullsize keyboards. Getting a bigger laptop won't make it easier to type on. I grew up on windows, but I want to buy a haswell macbook pro when they come out. The model I want will set me back just under 3k, but I got over the price, and I know I'll be happy with the purchase. If you want the best of both worlds, I would buy a mac if you can afford it, and set up boot camp. (Thats my plan on my future mac) Its not that difficult honestly. One of your friends probably has done it and would be more than happy to help. If money is a bit of an issue you can probably find a nice generation old windows 7 laptop on amazon or newegg. Just read lot of reviews and watch out for overheating issues and stuff.

The last three computers I've bought have been refurbished Dell Latitude laptops from the Dell Outlet. The only reason I upgraded was I wanted something newer/faster/with more memory than before; even the ten-year old one (D600) is still working just fine, and my five-year-old one was my everyday work computer until recently (when work bought me a dedicated work computer). You have to go into their Small Business outlet, but it's not like they ask for a tax ID. With a coupon (they always have coupons, you sometimes have to track for a couple of days) I got what would be priced at $1300 built new for $780, and keep in mind that I needed this to do computation-intensive work (MATLAB and R, specifically, which applies to you) and for gaming. The three in question were a D600, E6400, and E6430, in 2003, 2007 and 2012 December respectively. I'm unwilling to say "A $300 laptop would be very slow for numerical computation," because I have no idea what scale numerical computation you want to do, but... even though you say you know nothing, you know best what computational power you want. The rule of thumb is always more memory = more speed in numerical computation (and for things like MATLAB and R, your memory is the absolute limit on the size of your variables); as for CPU speed, I found http://www.cpubenchmark.net/ very useful. For an easy comparison reference, you may want to compare the CPU you find in the computers that are available for sale with the CPU in your lab computer.

Step one: Walk into Best Buy or another local big-box store that sells computers. Wal-Mart and Staples/Office Max/Office Depot will do just as well. Step two: identify your price point and and must-have features like screen size. Step three: buy the laptop on sale at the store manufactured by a reputable company (Lenovo, Dell, HP, Acer, Asus, Toshiba, Sony, etc. If you haven't heard of it, pass). And you're done. Laptops are basically commodities these days.