Fire Red was my first ever Pokemon game,so yeah.

Mine was Diamond

Mine was diamond two.

I like Charizard better, so I go with Firered.

I like Fire Red's color and mascot better (red and Charizard) BUT Leaf Green has several version-specific Pokemon I like more.

I'll never forget how I got FR as a young teen and kept looking for a Sandshrew, Vulpix, Staryu, and Bellsprout (respectively), and got so frustrated when I couldn't find them. Then I looked online and found that all my favorite Pokemon were in LG (including Johto Pokemon!), whereas a bunch I didn't really care for (Ekans, Oddish, Psyduck, etc.) were FR-specific. Again, I may like Charizard more, but I can choose a Charizard in LG but can't choose several favorites in FR.