The gnomes make me laugh, I don't go out of my way to collect them, but if my sims find one I just pop it in the garden, give it a name and let it get on with whatever takes its fancy. The baby gnomes are very sweet, the teen gnome is funny, the evil gnomes (my child got 3 from trick or treating) give my sims nightmares and the spring gnome is always in the way of the shower, I've never had mine gang up on any or kill each other though, I'll watch out for that. Heres a few random selections, inclucing babies :)
http://lvlt.thesims3.com/sims3_asset/sims3_asset/media/shard000//shard000/420/199/015/00/screenshot_original.jpg"width=300"
http://lvlt.thesims3.com/sims3_asset/sims3_asset/media/shard000//shard000/416/199/015/00/screenshot_original.jpg"width=300"
The one odd thign I have noticed though is the mysterious gnome has a tendancy to appear overlapping another gnome, which can sometimes be amusing all by itself ;)