I might get in trouble for saying this, but I don't think there are any Charlotte breweries that belong on a "must try" list.
Here are some NC beers & breweries on my "must have" list.
-Duck Rabbit Brewery's "Milk Stout" (Many Gold medals for this beer)
-anything from Foothills Brewery, especially if you find their "Sexual Chocolate Stout" which won Gold for at GABF.
-Olde Hickory Brewery's "Irish Walker." This may be hard to find, but you've struck gold if you do. (Many Gold and Silver medals for this beer)
-Highland Brewery's stuff is pretty easy to find in NC. They were one of the first successful microbrews in the state. They don't have a beer that knocks my socks off, but they have a solid roster.
-Cottonwood Brewery (now owned by Carolina Brewery) puts out what I think is the best pumpkin ale out there. It's pumpkin pie in a glass.
-Natty Greene's Brewery puts out a double IPA called "Cannonball." It's probably my favorite double IPA....nice balance between hops and malt. It's art in a glass.
-Asheville Brewing Co puts out some nice beers, especially their "Shiva IPA"
That ought to get you started
Octoberfest is THIS weekend in Charlotte. They are sold out, but if you could snag a ticket you would be attending the best beer festival in the state.