I would look for a 7200 rpm drive but if you have to buy one of those, get the one with the 16 meg cache. It will perform better. Western Digital and Seagate are now or soon will be the same company. Laptop hard drives now come in 7mm and 9.5 mm versions. The 7mm are required for Ultrabooks and other very thin laptops and 9.5 mm drives will not fit in a 7mm slot but a 7mm drive can be used in place of a 9.5 mm drive. The mounting holes and connections are in the same location and the thin drive just rides a little lower in the caddy.
My suggestion:
http://www.newegg.com/Product/Product.aspx?Item=N82E16822145587
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