Most of my family live in or around Northampton and as far as the town is concerned, there are good and bad points to every area. Some of the older parts and especially the older villages are lovely. My sister lives in Earls Barton, a largish village that has a lovely community atmosphere but very hilly!
The town of Rushden is another place that I regularly visit. Like many towns, the actual town centre isn't what it was but there is the Rushden Lakes Shopping Outlet about 10 minutes away (apparently it is walkable, but haven't done it yet!) that has shops, restaurants, a cinema as well as a lovely walking area around the lake.
You really need to decide exactly what you want - many of the villages and some areas are not covered by public transport. But also many have what you might need - GP surgeries, libraries, shops etc. Railway stations are Northampton, Kettering and Wellingborough. Just make sure you do your research and possibly make a visit for a few days to check out your options before planning anything and chat to local people if you can - Northants people are pretty friendly on the whole !
I live over the border in Bedfordshire, and that is a different story!