Heyyo,
I'd go for standard edition. N' as for hl2 no steam? I'm sure that steamlessproject site will think of something. As long as you buy the game, it's morally ok I say.
And as for HL1: source, I diddn't hear aboot it at all untill you mentioned it huntkillaz. Is it HL1 singleplayer campaign maps just converted to HL2 Graphics, etc?
So I'm guessing for HL1: source, you could get it online through steam, just like HL1 n' opposing forces?