What boat ... ??

Oops, misunderstood again.  I meant that the feva and RS200 are small for 2; the L2k is fine.  When on safety duty I've occassionally assisted overpowered Laser 2000 couples back to shore by acting as extra ballast.  Even 3 adults can have fun if there's enough wind.

... but the L2k's still slow and boring in medium winds and uncomfortable to sit on the side of if it's windy enough to perform well.  The gunnals are too sharp for easy hiking and the controls are a long way down in the bottom of the boat.  Bit "sit up and beg" for my tastes .... but many many disagree.

Your initial suggestion of the Vago wasn't that daft - would certainly keep the kids interested longer than a L2000, which are for old women

I'd say see what folk are racing at your local club and get something exciting.  If you get out regularly you'll soon learn how to sail it and your kids will be more inclined to take part.  The Topper Xenon is another option - they look quite interesting and have a reasonable performance, no maintenance, big comfy modern boat etc.

the feva would be good for two kids as long as they arent too big, it needs a small crew to get under the boom. you would be hard pushed to get an adult and a child in it and you certainly wouldnt fit 2 adults in it.

RS 200 is probably a bit too ambicous for you, as has already been said its twitchy and more of a racer without room for a third person.

the easiest boat to own (i.e lowest maintenance, easiest to sell on) would be the laser 2000 because you could race that and sail it around with kids but expect your kids to want rid of it or have their own boats shortly.

i dont know about ospreys, never even seen one close up.

perhaps a laser 2000 for a year then a laser each for the kids or feva/200 depending on their size and if they want to sail together still. not sure what you would want to sail.

one more thing to consider is what is sailed at your club because it's much better to have boats of your own class to race against.

The feva is a pretty good boat for a couple of 13 / 14 yr olds or a single handing adult or an intermediate adult and a preteen.  It's easy to sail. 

The RS200 is a rather twitchy two hander for reasonably skilled lightweights.  Significantly racier than the Laser 2000

Neither have room for 3.

The osprey is a huge muscle boat for big hairy men! (Haven't sailed one to be honest - but they do look that way )

Truth is, you never find a boat that does everything - and the price of a reasonable L2000 (£5000) will get a decent 3000 (£2000), an old laser 1 (£1000) and a pico (£1500) - of course the berthing fees are higher!