I go to about 65 concerts a year, which makes it one of my biggest "discretionary" line-items. Though as Russ says, it's a conscious decision, and the fact it's not just one amongst many stupid things I burn money on (I don't have a Starbucks habit, or a shoe-buying habit, etc.), means that I'm comfortable with it.
Even then, the total ticket costs mount up to only a little over $1000 per year (averaging about $17 per ticket, including fees), or about 5% of my total spending. It sounds like you might have already discovered the big secret that allows you to see awesome concerts for less than the $200 Madonna/Pink Floyd/Eagles charge, but I share this for the rest of the world unaware of the Mustachian hacking involved in concertgoing:
BECOME A FAN OF UNPOPULAR BANDS! This totally works out, because at least in music, popularity has no correlation with quality. It is, however, highly-correlated with ticket price. This is because most music listeners are lazy, and decide what bands they like based on what the radio plays, or what their friends like, etc. When everyone does this, it means that a relatively small set of artists are able to get hordes of music fans to glom onto them, resulting in an extremely unequal distribution of fans amongst artists. This allows that small set at the top to charge a lot of money because of the basic supply/demand law. Meanwhile, there are tons of equally- (or more-)awesome bands at the other end of the distribution curve rocking out in obscurity and charging only $10. This unequal distribution of fans is easily exploitable by the conscious Mustachian for big savings.
Said in Mustachian terms, most people "outsource" their music-tastemaking. "Eh, I don't care enough to dig around the millions of bands out there to find something I like, so why don't you just tell me some, Mr. Billion Dollar Multinational Entertainment Conglomerate." And just like anyone you outsource to, they aren't nearly as interested in (or even able to) maximize your value per dollar as you are. Insourcing the music-discovery process certainly takes a lot more time and effort, but like most DIY work, it's also much more satisfying. Not only can you achieve a tremendous cost-savings, it also gives you the opportunity to be Mr. Cool Music Tastemaker. "Oh, you're going to see The Burnt Flames at MegaCo Arena? That's cool. I saw 'em 8 years ago at a packed sweaty bar for a $5 cover when they were a bunch of hungry 22-year-olds pouring out their souls, so I'll probably skip 'em this time around, but, uh, I'm sure you'll have almost as good of a time...?"
But that means you have to have the fortitude to let your "favorites" go by when they get too big for their britches. I skipped seeing Nick Cave and the Bad Seeds last night (who I love) because the ticket prices were just silly. I didn't feel the least bit bad about it because #1) I'd seen him before (both w/ The Bad Seeds, and, more economically, with Grinderman), and #2) because last week I saw Bajofondo (led by a 2-time Oscar winner!) for $25, as a rare Anglo amongst a wild bunch of Argentinians and Uraguots, and also world-class singer Anneke van Giersbergen playing for 70-some old metalheads in a dive bar for $19, in her only North American stop in 6 years. Yeah!
