Oddly enough I've completely fallen in love with sweater dresses this year, though mine are not the 'big jumper' type - more very sleek, minimalist long dresses that happen to be knitted.
First one: High necked, long tight sleeved, cream wool maxi from Co. (Not Co.) Reduced in a sale. Absolutely beautiful thing but reaches the floor, so impractical unless I belt it shorter, which slightly spoils the shape. Belted, I've worn it with knee high boots. Full length, with big clumpy Grenson type ankle boots. Planning to try it with a short sleeved t shirt or knit worn over it when it gets colder.
Second attempt was a deep V neck, sleeveless Gabriela Hearst midi. (Massive discount in a sale.) Sent back because too big and too long and drab colour. And actually the wool would have made it too hot for sleeveless weather.
Third: ivory silk and cotton rib knit (looks like wool), sleeveless maxi from Loulou Studio. Narrow from neck to hem. Really easy to wear, Summer or Winter, with or without another layer over. Sandals or ankle boots.
I've also seen lots of cheaper versions everywhere but I don't need another for going out in. I guess the big jumper type might be nice to wear at home - but I wouldn't be prepared to pay for pure wool or cashmere just to wear for Strictly / Big Brother watching.