Try Notepad++. It's free, so you don't lose anything. Furthermore, it's GPL, so if you're interested, you can modify it, it if needed. I did use it before switching exclusively to Mac, and it was really nice. I don't remember hitting any issues. For programming, it offered highlighting and parsing (collapsing etc.). Your requirements:
- Advanced Find and Replace functions (replacing line endings would be helpful): yes. Supports also
\t etc., and regular expressions for more complex patterns.
- See control characters in my text: yes, "View -> Show symbol -> Show all characters"
- Add control characters to my text: yes, at least with hexeditor plugin (search for "hexeditor" from that page).
- Read multiple files at the same time (tabs and side-by-side view): tabs yes, and fully customizable. I'm not sure about side-by-side view. Based on this superuser answer, yes: right click on tab and select "Move to Other view".
It's almost as simple as basic notepad, but contains quite a bit of features:
- Syntax Highlighting and Syntax Folding
- User Defined Syntax Highlighting and Folding: screenshot 1, screenshot 2, screenshot 3 and -screenshot 4
- PCRE (Perl Compatible Regular Expression) Search/Replace
- GUI entirely customizable: minimalist, tab with close button, multi-line tab, vertical tab and vertical document list
- Document Map
- Auto-completion: Word completion, Function completion and Function parameters hint
- Multi-Document (Tab interface)
- WYSIWYG (Printing)
- Zoom in and zoom out
- Multi-Language environment supported
- Macro recording and playback
- Launch with different arguments