I’m from Welwyn Garden City which is 15 minutes away from St Albans, a few things for you to bear in mind:
St Albans is only 20 minutes from St Pancras on Thameslink (which also goes through Kentish Town) so you could access the northern line at either Kentish Town / Kings Cross - St Pancras if most of your clients are in North London. You can also pick up the Victoria or Picadilly Lines from Kings Cross - St Pancras which will take you to the other parts of North London (or there’s all the buses from KX - SP)
Angel is 1 stop from Kings Cross St Pancras on the Northern Line.
St Albans itself is a very nice place to live, good shops, huge market on Saturdays, lots of nice places to eat, quite a lot of bars and at least one Nightclub (it’s been awhile since I’ve had a night out there). Some of the University of Hertfordshire is based in St Albans, It’s also only 10-15 minutes away from Hatfield where the bulk of the University of Hertfordshire is. The only issue is, as its a nice place, it’s also pretty expensive.
If you want to live somewhere in London with easy access to St Albans, Camden or Kentish Town are probably your best bets due to being close to Thameslink but that’s not necessarily going to be any cheaper for you.
Hope that helps a bit!