Your best bet would be to wait a few weeks to find out exactly what all the different leagues are planning for the 2007 season, and then make your mind up.
Different people are going to give a different answer to your question, because no league is right for everyone. There are a lot of considerations to take in to account: format, cost, travelling, peer group, competition level, sponsor's support, and a load more. Until you are armed with all the details about which league is planning what for 2007, its a bit of a shot in the dark.
The NSPL will be posting all of our plans on this forum in January and as with the other leagues, we have a lot of exciting developments. For sneak peaks, check out our own forums.
Good luck to you and your team wherever you decide to play in 2007 - I'm sure you'll make an educated choice and that will then be the right one for you.