I am also quite surprised at the love of Lancaster and the hatred of Preston. I don't think the city (more like town) centres of either are particularly great. But as others have said, both are great bases.
Preston has Avenham Park in the centre which is lovely, Docks are pleasant for a walk (also have a dragon boat team if that appeals!) and Harris Library, Museum & Art Gallery is worth a visit.
We are in South Ribble, easy to get to the Lakes, Trough of Bowland/Ribble Valley and Rivington areas for countryside and great walks etc. Equally can be in Liverpool or Manchester city centres in under 1 hour (driving or train) for better shopping, more varied restaurants, plenty of theatres etc. On West Coast mainline so about 3 hours on train to London, Edinburgh, Glasgow. Easy to get to the coast - Southport, Lytham, Blackpool, Morecambe Bay. Easy to get to both Liverpool and Manchester airports (& we have even used Leeds to add greater choice to flight times & prices). We are on the motorway network within 15 mins but if there is an incident on the motorway the whole of Preston can grind to a halt.
There have been a lot of new housing estates recently so the house builders must think people will want to live here! Downside we are losing a lot of green spaces and farmland.
I always feel Southport is out on a limb because it is not far away from us but for longer trips it is added time to get to the motorways or hub railway stations.
I will also throw Longridge into the mix, don't know what it is like at night but lovely during the day. Has a Sainsburys, Booths and Co-op and lots of small shops and micro bars and cafes.
Your DH's job and any commute will be a key consideration.