Both 1988 and 2006 are class. However, I have to go with 1986. Not only are the three album songs H wrote on SiT great, he wrote them all by himself. That's unique for that album. In fact, these three songs are the only ones on all Maiden studio albums where H is given credit alone. On all other songs where he's credited, it's along with either 'Arry, Bruce or both (except Gangland, where Clive Burr is co-credited). So, 1986 it is.