XML is fine if you have a good reader/writer library to accompany it. Writing your own is never fun (IMO), but that does not mean you should roll your own custom file format. There is a point where you should look at a scripting language to integrate into your game, but for simple configuration files XML is no big deal at all. Keep doing what you’re doing!
You could also look at JSON as the data format (in my opinion it looks cleaner) or for scripting use a purpose built language such as lua.
I have my own libraries for JSON and XML. I use XML for formatting objects and JSON for saving/loading them.