Thanks for the nice words, elecbzerk.
www.wetwebmedia.com is an excellent source of reliable species information. I like all Scott Michael's books, too. Also search by species or group of interest on Reefkeeping online magazine, associated with this site, and advanced aquarist online magazine.
Personally, I would not get the clown trigger. There are other really nice triggers that you can keep as adults in a tank like yours, that have less chance of eventually killing tankmates. I had a small (less than 3") clown trigger that attacked and killed everything I had, except for an even more aggressive eel. I have not been tempted to keep one again in a tank with other fish, even though they are so beautiful. I would consider having one again if I had a larger tank than my 210, and was willing to devote pretty much the whole tank to the trigger. If you read up on the triggers, there are quite a few that are really colorful, moderate sized and outgoing, and less likely to be so aggressive. Most of the Rhinecanthus triggers fit the bill. Take a look at the Assasi - it is a bit more expensive and rare than a picasso, but very cool looking.
A dogface should do fine in your tank as an adult, but a porc would be pushing it, IMO. There is a nice burrfish that stays about 10". I don't have experience keeping that species, so I don't know how difficult it is.
There are some hobbyists that successfully push the envelope on tankmates, like danorth. However, since you are starting out, and since you have kids that may get attached to the fish, I'd go with safer choices to start. If you get as addicted to this hobby and the fish as many of us are, you'll have more tanks soon for your nastier choices.

BTW, if you decide you want a single, beautiful trigger, consider an undulate in a species only tank. I think a 75 is about right, but others say a 55 will do for a long time...
The southern puffer was in my LFS as a "long nosed puffer". It's similar to the puffers I used to fish for on the bay side of long each island in NJ when I was a little kid (I think they were probably northern puffers). If you want one, I'd contact a Florida collector like divertom.com or reeftopia.com and see if they'd catch you one. make sure they know it's not a valentini puffer. My southern puffer makes a nest in the sand to sleep in at night, but swims around a lot during the day.