I'm not sure wether your new to vibrators or not but I'd start with something simple.
I have this one, It's great even though it chews through batteries so quickly, it's also quiet for a vibrator which will be good for the kids - http://www.lovehoney.co.uk/product.cfm?p=16603
the question is, what is your budget and what is what you are looking for in a toy. A bullet vibrator? Vibrator which can be used internally? Or a dildo?