I guess it depends on the airport, but I've found that prices are lower when you check on weekends (not that you fly on a weekend), but that for some reason their rates are lower when I log in on say a Saturday and check for a fare. That's just been my personal experience, but it's worked 3times.
Also, unless you know your route to be full, I would advise against the $11 per person charge to select your seats. I haven't known anyone who has had a problem with sitting together; not to say it wouldn't be a problem if the flight were full but I don't think it's worth the money for say, 4 tickets roundtrip...that's $88.
Also, I have found that when they first release the schedule the tickets are not necessarily at their lowest point. It's best for you to research other days/times and see what they are 30 days out, 60 days out, etc. For instance, my route from FAY to SFB can be as low as $29 each way within a month of the trip. So, I wouldn't book at the earliest opportunity if the flights were $79 or $89 each way; knowing that they generally drop. For my route, $39 is a good deal and that's what they're at right now for flights prior to the first week in February.
Again, if you are on a particular busy route, this theory may not hold true.
Just my $.02.