HSM is a safe bet (my eldest daughter is 10) over here in the UK at the moment, even if they're not really "into" it, it'll be something they can use in school and fit in (binder, pencil tin etc)
Also at age 10 it depends very much on the child- my eldest daughter it would be books, entirely books- from anime novels through to Gemmell, Pratchett and Tolkein, she's a big time reader and very able. Also she enjoys a variety of crafts, alot of bead work. Her bestfriend however is all about water- swimming clubs, scuba etc, her other friends one is very into dance so hair accessories (very, very sparkly ones) are always a great idea as she wears them for competition dance.
Webkinz are fairly new here- do they require community interaction on a public website or is it individual websites? As some parents might be web-safety conscious. We have little starz here too where a star is named for the child when you buy the fluffy toy.