Favorite Pokemon theme song?

It may seem strange, but what is your favorite Pokemon anime opening theme song? it can be one that brings back memories.

I liked The original/Orange Islands because they remind me of watching them when I was younger.

So what's yours?

Challenger!!

The Battle Frontier Theme from the Advanced Generation series. It was just...so catchy to listen to. So nostalgic, also.

Well nothing beats the original (ugh XY had that horrible cover), but I have to say Battle Cry is my favorite its just so inspiring.

The original. :)

I like:

Original (including XY cover) and Orange Islands.
Johto Champions
Advanced Challenge and Advanced Battle
Battle Dimension and Galactic Battles.

Nothing can top the original. I do really like Pokemon Johto and Born to Be a Winner.

Of course I'm biased towards the original, but I loved all of the Johto themes and the Advance, Advanced Battle, Battle Frontier openings too. The Johto songs are really nostalgic to me and were catchy, as for the Hoenn songs I like I find them really cool and the tunes are so good.