The Windows registry is just a database that sits on the file system. Parts of the database are maintained in memory for extremely fast access. The database also handles locking when multiple applications need to have access, or write to the same piece of data at the same time. The registry was made to replace the need to keep the following from happening...
(My application needs and INT value that describes something.)
1. opening a file.
2. locking a byte range.
3. seeking to the byte range on the disk.
4. parsing the byte range.
5. performing ASCII/UNICODE to numeric INT/DWORD/LONG conversions where required.
6. re-writing the byte range (when required).
Since there are no numeric conversions, this also takes care of keeping values small, and taking up less disk space and speeding things up as well. The registry also has ACLs for the data.
If you've ever watched access to the windows registry via applications through hooking programs like regmon, then you will note just how much you need that speed and accuracy.
There's nothing "special" or evil about the windows registry. It's just a miniature database "data" file system on top of a larger file system.
It's global, but your applications don't have to use it if you don't want to. For your applications to have Windows logo certs, you would need to apply certain registrations of software install information in the Windows registry, but that is about it. You don't need to store any of your applications' data in the registry. You can just store things in text files if you want. Slow poke.
This myth about what the Windows registry is just lame and probably comes from being absent minded about other technologies and ways of doing things.