I bought tickets in advance. I lucked out on ticketmaster and managed to get a pretty good seat. Which city are you trying to go to? That was like my dilemma too .. even though I had a ticket, I kept checking will call to see if they released more and I would buy a better seat. I got there earlier in the day and was waiting in line for them to come out.. but it was so crowded and I was afraid to lose my spot to check with will call. Finally at about 4 something, the guy came out and said the Idols got delayed in traffic and would not be able to come out and sign autographs. So I waited out there for nothing basically.
Honestly, check ticketmaster the week of the show. They release more. Even the day of the show, they had 7th row seats. Which show are you trying to go to?