find all files except e.g. *.xml files in shell

Sloppier than the find solutions above, and it does more work than it needs to, but you could do

find . | grep -v '\.xml$'

Also, is this a tree of source code? Maybe you have all your source code and some XML in a tree, but you want to only get the source code? If you were using ack, you could do:

ack -f --noxml

find . -not -name '*.xml'

Should do the trick.

find . ! -name "*.xml" -type f