HTML, 96 chars

Leonardo DiCaprio 

This works even with the strictest rule (no space, no letter case-insensitive).

HTML/Markdown, 96 bytes

Leonardo DiCaprio 

This works even with the strictest rule (no space, no letter case-insensitive).

Markdown, 194 - 100 = 94 bytes

This is the fancy version, so it uses quite a lot of bytes (UTF-8). At the end of the first 2 lines are 2 spaces.

╔════════════╗ ║Leonardo DiCaprio║ ╚════════════╝ 

How it looks (may or may not look good depending on the font face):

╔════════════╗
║Leonardo DiCaprio║
╚════════════╝

Markdown, 142 - 100 = 42 bytes

This is the poor man's version. No Unicode character is used, so quite lightweight.

~~~~~~~~~~~~~~~~~ | Leonardo DiCaprio | ~~~~~~~~~~~~~~~~~ 

It looks like a cookie to me:

| Leonardo DiCaprio |