My word of caution would be that "the itch" isn't terminal... Everybody, at one time or another, gets a "need" for a "high volume plinker", "tactical rifle", "black rifle", etc etc, but after the new wears off, you're basically left with a $2000 toy sitting in the safe collecting dust. You'll be so excited as you spend a few hours loading up a dozen 30rnd magazines, and you'll love the rush as you tear off shots as fast as your finger can twitch, but then at the end of the day, your accuracy sucked and you just blew $100 of ammo, and you spent 2hrs loading magazines, only to blow them empty within 20min.
Don't get me wrong, I'm a HUGE fan of the AR-15 platform, and own several. I also build custom AR-15's. I'm not a fan of the 4 rail "tactical" styled AR-15's, but I have a lot of customers with "the itch" that order them.
Where I think the AR-15 really shines is on the bench. Admittedly, no, it can't keep pace with a top end bolt action rife, but many of my rifles have acheived 0.5-0.25MOA accuracy, even with factory ammo. For the competitive shooter, it's an advantage to have a semiauto so the shooter can minimize shot to shot time, allowing them to shoot a group quickly while wind conditions are relatively constant. The accurized AR-15 semiauto also eliminates the necessity to move to cycle the bolt, so the shooter can retain his consistent shooting position from shot to shot. For long range coyote or prairie dog hunters, or for heavy brush hog hunters, it's also an advantage to be able to deliver quick follow up shots while keeping the scope on target. Which is also a huge advantage while tracking running game.
One day sitting over a prairie dog town with an accurized AR-15 and you'll be hooked for life.
But again, most guys get a "rambo complex", aka "the itch" at one time or another, so they'll seek out a "tactical" 4-rail AR-15 and spend $2-3,000 on the rifle and accessories, only to realize that they have no real practical use for it.