HEL sounds interesting, but the fare structure is only economical if you are prepared to spend a Saturday night, meaning that Hotel accomodation comes into play.
At the moment I'm leaning towards an AMS daytrip + a UK domestic flight or 2 x AMS if I really like the place. The Hotline fares are really decent.
Your call....although I've never been able to get my head round the fact that a lot of you tier point runners don't want to stay even one night at your destination.
Seems crazy to me....I suppose being crazy is what makes you do such things in the first place.