I'm a big fan of Charnock Richard services in between Wigan and Preston, it's good because the Burger King and KFC are actually on the bridge over the M6, so whilst enjoying an XLBDC you can be mesmerised by the flow of traffic below.
As a kid, my dad bummed off Tebay services in Cumbria. Sure it's in a nice setting but the amenities and quality of fast food are very poor. Possibly the most indie services, however.
I've also got a fondness for Newport Pagnell services, but think i've only ever stopped there on the northbound side. Good Burger King there, seats are a bit low though.
Honourable mention goes to Telford services on the M54, nice high ceiling in that one.