Gah, the discounted price is €45? That's insanely expensive, IMHO! In my mind, the Portal franchise isn't comparable to "regular" games, and I think Valve are creeps for pricing their downloads so high - when cutting out the whole physical media and regular delivery chain, prices ought to be craploads lower. WoW:Cataclysm, including physical media and delivery, is €30.
But I'll probably still sucker up, while cursing through my teeth at Valve, and longing for more HalfLife goodness.