I don't remember specifically, but I'd've been living in Edgecombe House in Southfields with Jane, flatsharing with university friends Bella and Alexis. It's possible I might have started doing a summer job by this point (I think I worked in the offices of a local newspaper two years running, and this would've been my second year). More than that, I can't remember.
Chamber of Secrets came out (2nd July 1998)?
I'd finished university by this point, although I can't remember when the actual graduation ceremony was, and Jane and I would have been either living in Swanston Gardens or in the process of moving (or had moved) to Stapleford Close. I don't know for definite, but I don't think I did any summer work this year.
Prisoner of Azkaban came out (8th July 1999)?
Jane had left me, I was in the process of moving from Stapleford Close down to Chelmsford very much against my wishes. I was still travelling between the two on a fairly regular basis, and IIRC it was about now that I first became aware of Harry Potter - I'd often catch the number 35 from Clapham to Liverpool Street when I was heading back to Chelmsford, and I saw the books in the window of the Clapham branch of Ottakar's.
Goblet of Fire came out (8th July 2000)?
Living in Chelmsford, unemployed, still depressed from the whole breakdown of my marriage. By this point, the Christian press had started to notice Harry Potter and was printing occasional articles about how it was promoting witchcraft and was a danger to young people. I never entirely fell for that, but I had little interest in Harry Potter anyway, so I just steered clear of it.
Order of the Phoenix came out (21st June 2003)?
My divorce from Jane was nearly finalised. I still wasn't bothered by Harry Potter, but Tim was buying them as they came out, but not bothering with late night queues or anything like that - just popping into the local 24-hour Tesco at just gone midnight and picking it up without any hassle.
Half-Blood Prince came out (16th July 2005)?
I'd now been sort of introduced to Harry Potter by a friend called Debbie - I'd watched the first two films on DVD, and then gone to see the third on its opening the next day. So that was a bit of a baptism of fire. (And I still love the third film, and I still think the films are pretty much playing up the Harry/Hermione angle, so it's still canon as far as I'm concerned so there..!) However, I'd not bothered with the books yet. I do remember what I was doing this weekend, though - Sarah and I had gone to Bedford for the weekend, amongst other things to see the John Bunyan museum and go to the Bunyan Meeting Free Church. If memory serves, we visited a transport museum on the way back (and I saw my first Sinclair C5...). By the time we got back to Chelmsford, Tim had bought Half Blood Prince, but not finished reading it.
Deathly Hallows came out (21st July 2007)?
By now I'd read all the books in order - starting around the start of June, and finishing on Friday 20th July. Couldn't wait to see what happened next! How did everyone else cope waiting a whole two years??! Went to Sectus, had a great time, joined a midnight queue for the book at the local Waterstones, did the "reading through the night" thing fuelled by a large bar of Cadbury's chocolate, spent large chunks of Saturday in a daze (partly because of the thrill of the whole thing, partly 'cos of lack of sleep). Bits of the book made me laugh, bits of it made me cry, it thrilled me, it excited me, it shocked me, it was a wonderful end to a wonderful series of books.
At some point I'll have to re-read the whole lot.