I've taken the time to let the details of this sink in, having personally gotten quite pissed off at the prospect of pay to play HL2. But now I understand what Valve are doing I still don't like it.
Okay, I'm going to buy the retail +SP+MP+Mod-sub version from a store - I'll be able to play the single game through, get fragged a lot online and install the odd SP or MP mod that eventually comes out. Now for at least 4 to 6 months there will be no new non-Valve content worth a damn but there will a scheduled release of new content on Steam to make the subscription appear more attractive. And what about the mods that gave HL such a shelf life - new versions locked into Steam deals.
I think what I really dislike about this is that no matter what I do there are going to be disadvantages. Between HL1 and HL2 was what, 4 years? That's $480.00 if you want to keep playing and keep up with new content before the next major iteration of the series. (HL3...)If you just want to dip in and out of the game and you're buying all the content as retail boxes (say 4 expansion packs a la HL1),
it's costing you less, you have the flexibility to install/uninstall the game fairly easily, you can even lend the game to your friends and family BUT you'll never have access to all the content.
So now, just thinking about this again, I'm getting stressed that I'm going to have to subscribe to make sure I have everything, but then the sub will sit idle for months at a time while I'm engrossed in some RPG or other MMOG. And as somebody somewhere has already said, if it works for Valve then everybody else will jump on the bandwagon. So what happens when mod authors are automatically getting locked into agreements only to host their mods on official game servers? Valve aren't forcing this on anyone but you can be sure some producer/publisher somewhere will.
And what about people who through geographic location have no access to broadband?