
120GB is fine, but overkill is correct.
Im sure if you search you tube you can find a video tutorial on how to do it.
Any HD is fine, but I recommend Seagate from my personal experiences.
But honestly, If your in fairly new to this, to the point that your having to ask about how to install the "harddrivers"
then I would strongly recommend just purchasing a large compact flash card.
like a 32gb or 64gb. which will run you close to the same price a hard drive would, but a CF card is easy to swap for another on the fly, plus they dont make noise, get hot, or mechanically FAIL.
Plus you REALLY dont need 120GB of space for samples, let alone in a sampler that only has 128mb or ram, and a 998 sample limit at max. Even if you save everything you have loaded, every time, as a project, and keep duplicating the same sounds in different folders, it will take you a long time to use up 32gb to 64gb. then If you fill it up, just buy another card, and swap between the two. its win win.
trust me. get a CF card.
"The intuitive mind is a sacred gift and the rational mind is a faithful servant.
We have created a society that honors the servant and has forgotten the gift." by: e=mc2