Are you looking for a hosting plan or a dedicated server? If you are looking for a dedicated server to store files (this is the dedicated server forum ) any host would do for you and most of them usually have the option of adding a extra hdd for you if you really need to host a large amount of data.
Just to note: You could also turn your computer into a small webserver and grab things through that for the price of adding a 120GB HDD to your current computer.
Otherwise, almost any server company can accomodate you. I suggest going with a semi-managed provider and making sure that beforehand they don't have a problem securing the server initially and having it setup the way you need it done.
If you email managed dedicated server providers, and let them know they will probably cut you a deal on the server since you don't need cpanel, and you only need apache management get's significantly easier. (and it's easier to secure the box as well w/o exim, php, mysql running).
Heck they might even have a box on-line doing something else that they can put you on just for file sharing.
Email 'em and see what they can offer you.
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