Yes. Notepad++ has a latest release 5.5.1 has some built in themes you can take advantage of. If you want little bit more customization, you can change the colors of every element in UI as you want.
Quick google search shows that there a vibrant community of TextMate(Mac Editor) has a good themes. http://joyboner.com/60-free-textmate-notepad-styler-themes/ will show you how to convert those themes for notepad++.
Step 1. Assuming you already have
Notepad++ installed, navigate your
browser over to the Textmate Theme
Step 2. Choose a rad looking theme and
Step 3. Fire up Notepad++ and open the
.tmTheme file you just downloaded.
Step 4. Select all (Ctrl+A) and copy
Step 5. Now navigate your browser over
to the theme converter page.
Step 6. Paste what you copied from
Notepad++ into the big textbox and
click the download button and save the
Step 7. In Explorer, navigate to:
Step 8. Locate the original styler
theme file (stylers.xml) and rename it
to something like original.stylers.xml
Step 9. Take the file you downloaded
from Step 6 and move it to the
location in Step 7.
Step 10. Rename the file you just
moved to stylers.xml
Step 11. Close Notepad++ and reopen
Step 12. Enjoy your new colors!
Hope this helps.