Server Applications:

 1. Web server with partial caching
 - A caching proxy
 - memCached
 - Relational databases
 - Indexed data, like lucene, or some kind of hash-table
 - virtualized servers

Scientific Applications:

 1. MatLab et al.
 - custom (or not) machine learning
 - various things like protein folding.
 - more stuff I'm not qualified to actually list

Media Applications:

 1. broadcast ready video stuff using uncompressed feeds
 - general video editiing, with scrubbing etc would benefit
 - graphic design. The less files you must close the more you can work on.
 - even music production can benefit, say you're working with 256 tracks and a lot of virtual instruments and effects patches, they all maintain state and buffers.

Engineering Applications
 
 1. Basically any CAD
 2. A lot of simulations that are updated to work with huge datasets.