In my 20-plus years as a season ticket holder, it's difficult to narrow it down to just 5 moments. This is what I've come up with:
1) Relegation in 1996 - despite a terrible first few months where relegation seemed like an absolute certainty, Ball oversaw enough of a revival that took us out of the drop zone only for us to fall back into it in the closing weeks of the season. The Liverpool players didn't seem particularly arsed that day, yet we still failed to beat them.
2) Relegation in 1998 - our worst-ever season IMO. We started it as favourites for promotion - mainly on the back of our form in the final few months of the previous season when Frank Clark took over around Christmas 1996. However, we struggled from day one of the 1997-98 season and it was a thoroughly disastrous campaign. There were plenty of shocking defeats that season but losing to Bury, Stockport, and Crewe summed up how crap we were.
3) The FA Cup Quarter Final defeat at home to Tottenham in 1993 - Like pretty much everyone else, I was beginning to think it could be our year after we beat Barnsley in the previous round and bagged ourselves another home tie. Nick Barmby was Spurs' star player at the time but Swales (being on the FA commitee at the time) did one of the few decent things for City (or so we thought) and insisted Barmby had to go and play in some World Youth tournament and would therefore miss the match. Unfortunately his replacement (some bloke called Nayim) scored a hat-trick as we were well and truly thumped.
4) The home defeat to United in November 1993 - already mentioned elsewhere, this was a catastrophic collapse after going 2-0 up at half-time. I disagree with Dave though - United were a miles better side, were reigning champions, and were runaway leaders while we were struggling near the bottom, and were in the middle of the Swales/Lee takeover saga. That said, it was still devastating seeing that second-half turnaroud and although there was an air of inevitability about it as we defended deeper and deeper, it didn't make it any easier to take.
5) Defeat to York City in December 1998 - our lowest-ever point in terms of league position, slipping to 12th place in the third tier. Thankfully, things improved from the following week with the 1-0 win at Wrexham. On the plus side regarding York, it was a cracking away trip!