There are tons of low-cost and costly alternatives... it all depends upon what you are interested in doing.
I've used XMLSpy and several similar, very robust tools, and I'm currently enjoying Microsoft's no-frills XML Notepad.
What are you planning on writing in XML?
Rosenman, many thanks for your suggestion. Planned use: text in a hierarchical (not relational) database, which can be manipulated and reconfigured in various ways for use in various print productions and also on a web site.