So how does one kill a program that will not close and is hogging up memory?
OWB does this sometimes when you try to download a file and it tries to load it as a web page instead.
What kind of link does that for you? If it happens, it's most likely because the server doesn't set the proper mimetype and sends for instance a binary file as text/plain, which OWB would try to display, by default.
Fortunately, you can change that behaviour by going to OWB mimetype settings, and adding the extension/mimetype for the link, and set the action to download or ask (similar to ibrowse mimetype settings).
But anyway, OWB shouldn't crash while viewing plain text files (unless it's really really big and webkit runs out of memory, not even sure it would).