Deskpilot, as a current Airline Pilot I would have to say - go with the IT opportunity. Everytime.
I don't know if your single or if you have a family to support but either way you need to have an assured future and at the current time flying does not offer you that future. It probably never will unless you make it into a legacy or major low cost monster where job security is pretty secure (never say never).
I've never had so much fun flying light singles and twins around the UK and USA, I've never had less fun than flying a commercial airliner. When you're on the outside looking in it's all glamour and the thought of flying jets or turboprops is all consuming and you'll feel that's all there is in life!! I know - been there. It's not like that at all. Sure to begin with its amazing and you'll love it but soon those 3am alarm clock calls 5 days in a row start to take their toll, particularly when your mates in the city (in my case) are doing slightly less hours than you put in but taking home twice the money!! You realise its work to live - not the other way round.
I appreciate the dilemma you find yourself in, having put so much into the flying up to this point it's a horrible thought to let it go however if you want my advice - take the IT job, take the cash and fly for the sheer fun of it. You'll have an absolute blast and you'll never fall out of love with aviation.
Good luck in whatever way you go
