Memory

No, not talking about mine (which is shot, btw), but about getting additional memory for our computer. I store our digital photos and videos, as well as a lot of music files on there, and it is really starting to eat up our space. I'm sort of torn between doing a memory upgrade (in which case, can anyone recommend a brand? I'm inclined to go with IBM memory for no other reason than brand recognition), or just buying an external hard drive. Opinions, anyone?