Is standard mode or blitz mode better for learning chess?

Normally I play 5 or 10 min games, but I was wondering if my chess would improve if I would start playing games with higher time limits.

That's what most titled players suggest.  Get good playing long games where you have time to figure out plans and ways to implement them.  Sure blitz is fun and of course titled players love blitz games, but with rare exception, that's not how they got good.  They got good playing long slow games and reviewing them afterwards.  And yes, I do expect to be told I don't know what I'm talking about.  If you're already addicted to blitz of course you don't want to play anything else.  We all love the rush you get playing blitz when all those happy brain chemicals (endorphins,etc.) kick in.  That doesn't mean it's good for you.  And yes I'm just a messenger parroting advice I've read from titled players so bring on the hate mail. 

Longer time limits are reckoned to be much better for learning the game than playing blitz. You have more time to think the moves through and gain a deeper understanding of positions which arise.

Standard.  There's no debate, that's the answer.