What boat?

well i think a wayfarer provides alot fo room and is very stable so would be good with a todler in tow, however you will also want to take into consideration the type of fleet present in poole harbour in case you want to race or just for advice.

the enterprise is a good 2 man cruising boat but you would be at a push to fit an extra adult in i reckon, i would go with the wayfarer personally fomr what  seem to be describing

I son't know, I remember going out in my dad's boat
when I was a toddler. Can't remember what boat it
was, some sort of wayfareresque day boat of some
sort... I've also got a '2 and a bit' year old sister, and
even though she's a serious handful, I think she'd
quite enjoy it. Soon as she's properly potty-trained
she's going straight into an Oppie!!

my dad used to take me out in his flying 15 from the age of two very stable and pretty fast with the kite up.

well i think it all depends on the experinces i mean perhaps if you were experiencing a new thing such as sailing at a young age or somthing with has a centimental memory then i think you can remember it.  but a flying 15 at 2- sounds gr8 fun lol, 

My first memory is being picked up by the ankles and getting slapped.

On a serious note a vareo could fit the bill.  I once borrowed one and there was enough room for my daughter who was six at the time to move around the front, it was suprisingly stable and the spini gave her some thing to do.  Even if I was trimming it and she just had her hand on the sheet. Plus if you get a girly coloured kite then there will be less protests from the missus.