I would advise against the Jack Russell Terror unless you have tons of spare time to devot to harnessing the energy those things have. They are super smart and that equals destructive when not properly occupied.
I know no one has mentioned it but I'm tossing this out as kinda of a PSA - Do not get a Dalmatian. Horrible shedders and not good with young kids as they have just as much enegry as the JR Terror but are at least three times as big.
Any of the long haired breeds (Malteese, Bichon, etc) are good as far as shedding goes, however, the grooming can be a bitch.
I've heard good things about Corgis (I'm not sure if they're bad shedders though).
You might look into an oversized Italian Greyhound (a normal IG is 8-15 lbs an oversized is 15-25 lbs) or possibly a Whippet.
Whippet resemble a Greyhound but are smaller - about 30lbs. They have short fine coats and hardly shed at all - supposed to be good with kids too.
Here is a link with more Whippet info