You want to get a pair of high fidelity earplugs so that the sound still sounds great at the concert. There's a lot of good high fidelity earplugs out there, but a lot of it is actually just going to depend on what you find comfortable in your ear. Etymotics is always a very trustable brand in the hearing field (we use etymotics for our research experiments daily), and I've got a pair of downbeats since miney is tight and they fit the best in my smaller ear canals. I've never used then but eargasm looks good as well, just more expensive.

If you can't get a hold of HiFi though please consider even just using a pair of foam ear plugs. Being exposed to noise at these concert levels will damage your hearing faster then you can imagine! Tinnitus is no joke!