I grew up in Worthing, in Broadwater in fact :), and was a really nice place to grow up in. From Broadwater you can easily walk up into the Downs and we used to go and climb the trees up there and do some really great walks. The Green in Broadwater used to have different events on in the summer. We also used to walk down to the beach and go on the pier, or for a swim, the Sixth Form College (the schools didn't used to have sixth forms so everyone went to the college instead, don't know if this is still the case) is near the beach in Goring and we used to go swimming in our free periods in the summer :)
I wouldn't have ever described Worthing as dire, the main high street always had most of the shops you need, they did a lot of work in the 90s modernising and pedestrianising large areas. The Guildbourne centre was definitely grotty - is that still there?
We only had an old cinema then, The Dome (is that still there?) which was pretty rubbish as we had to go to Brighton to go to the cinema, but Brighton wasn't far at all as the train was so quick to get there, so if you want nightlife and more shops etc. they are definitely very easily accessed. Sounds like there are cinemas in Worthing now anyway. Our nightclub used to be at the end of the pier
Worthing was never cosmopolitan, but Brighton is there if you need it. My parents moved to Worthing in the 70s as Brighton was considered very grotty then and Worthing was seen as more upmarket!
Worthing was always very sleepy with lots of old people, but for a family it has always been a nice place to live imo. I went to the local girls high school which was a brilliant school in the 90s, not sure now though. The boys school also had a good reputation then too. Competition was always fierce to get into these though.
I moved away in the early 2000s, as did my parents (they weren't originally from there) and now live abroad so can't comment on what it is like now, only what it was like growing up there, but I have fond memories :)