I have to say that the (brand) (model) in (size) of (durometer) is the perfect tire. Except when it's not.

i'm still pretty new to mtb but i figured all you guys would say change the fork first. tires wasnt something i expectd to read. my jet9 came with conti xking tires on it, i got a hole in the sidewall so i ordered some maxxis ardent tires to replace them. my buddy that rides them said they rail corners. i'm hoping they make a big difference, i need all the help i can get. i'm just now learning i need to put some weight over the front tire instead of leaning back. now it seems like a no brainer.

If people are going to post tires, brand and size can you also post typical riding conditions as well?

A typical ride for me starts with several miles of pavement, which gives way to several miles of gravel, which gives way to several miles of hard pack. The hard pack can have miles of relatively soft dirt and some loose sand. Throw in some mud and ruts. My Rockhopper came with Maxxiss Capitan studded tires or something like that. I switched them out for some cheaper Avernir Swiss Army universal tires I got from Dick's Sporting Goods for $17 ea and I couldn't be happier. The Avenir tires are much much faster on smooth surfaces and they grip well on dirt. The only places they slip more than the studs are on the loose sand or deep mud, and those are places I try to avoid anyway.
Maybe now I'll look into upgrading the fork.

helium.

Since tires, wheels and all of that has been mentioned. A comfortable set of handlebars.