Small hotel within 100m of Kings Cross, and 500m of St. Pancras was perfect for my purposes. Room was reasonable size, cool enough for me to be comfortable and had a nice en suite. The hotel is around the corner from a very nice Chinese restaurant (Bamboo Inn), so great for me as I love asian food.
Only thing to note is if you have mobility issues, the room I had in the basement might not be for you, it being down a short flight of narrow stairs.