I HAVE to have a Fire type. If for some reason I can't have one (like in a challenge), someone needs to know Flamethrower. It's my favorite move. Fire Punch, Fire Fang, or any other good Fire move will suffice though. Hell, even Hidden Power Fire. I'm not a pyromaniac, I promise. XD
I'm also not too keen on having more than one Water type. I have nothing against Water types, but there are just SO many and so many HMs for them...idk, I just don't like having more than one. But Water is another essential type that I need, just second to Fire.