There is no limit that the OS can take but there is oviously a limit to the size of the hard drives available. If you have a IDE hard drive then i believe your limit is 160gb but if you have SATA your limit is 200gb and in the next few months 250gb.
In my laptop i have 320gb (2x160gb) and im going to upgrade to 500gb (2x250gb)
I have a inspiron 1150 laptop, i want to buy a new hard drive and i was wondering if there was a gigabyte limit that the 1150 would support? also, does anyone have any recommendations on which one should i buy?