In terms of simply knowing about what shows are coming up, the local music scene's Internet presence has come a long way in the last four or five years. Nashville Cream is going to have a lot more shows and proably be more up-to-date. However, the old board was unique because there were great people to help separate the wheat from the chaff. You could always count on strong (but usually informed) opinions to help you spend your weekend more wisely. That's what I miss.
Both the Death Cab and Coldplay shows will be very good, I'm sure. However, I'm just not that into going to big rock concerts these days so I couldn't bring myself to even attempt to get tickets. Flaming Lips at Rites of Spring, however, could be a different story. They're always a lot of fun to see live...