I've searched and searched and can only find one 2.5 inch HDD that is larger than 1TB (Western Digital has one model). 3.5 inch HDDs have kept growing to even 10TB, but 2.5 inch drives seem to have hit a brick wall.  Are there any 2.5 inch HDDs larger than 2TB?
>2 TB 2.5 inch HDD
hard disk
Seagate has recently released a 5TB drive for $85.  It's also 5400RPM, but that doesn't matter much these days, because if you're very performance-sensitive, SSD is the way to go anyway.