The tastiest lamb cuts are (as usual) ones that require the most cooking. Shoulder, leg, neck and shanks are the ones i go for. I used to have roast lamb cooked to a nice medium but personally i think its much better when cooked low and slow until it falls off the bone. I think this works well because its such a fatty meat. I love lamb rack too but its just such poor value for money I refuse to buy it.
A few ideas that i like to do:
Brown shanks and braise in onion, leeks, carrots, celery, a whole bulb of garlic, rosemary, thyme, red wine and chicken stock. Serve with celeriac and potato mash and reduced cooking liquid.
Crispy mongolian lamb is also really good and packs big lamby flavour like crispy peking duck does.
Lamb cooked in hay is quite unusual and really delicious too but I've only cooked it once.
Lastly, for a super easy and impossible to mess up recipe, this is excellent:
http://www.bbc.co.uk/food/recipes/sl...ked_lamb_26033
Thinking of all this, I think I'm going to try and make some pulled lamb in the smoker when the weather warms up.