After number 2 released?

not unless they drop the price significantly. they have a pack which will net you l4d1 + l4d2 for $64.99 it's not a great deal, although I like to think of it as spending $50 and getting the expansion for $15, in reality you're spending $50 for the expansion and getting the full game for $15.
But seriously though, L4D2 adds a ton of new content, content that should have appeared in l4d1, and we all know won't show up.
It is worth a good hard think.

Wait until the end of the year. Valve are bound to hold another year end sale and at that point, they'd be stupid not to offer L4D up at 75% off. L4D2, though, you'd probably be lucky to get at 25% off in that sale. But buying L4D this close to L4D2's release is a bit stupid if you ask me.

I was sort of excited for L4D2 but after playing the demo I probably won't buy it for a few weeks until it gets marked down in retail (possibly wait for a holiday sale or something). And yeah, L4D will almost certainly be like ~$15 or less during Steam's yearly holiday sale which starts around Christmas. That said, you might find a copy retail for that right now and all of Valve's games can be activated on Steam.

I don't really think it's worth buying unless it goes down to a price that makes you think "Wow, that's pretty cheap!"

I'd say wait until Christmas week. Valve always has this crazy-ass sale where a bunch of stuff goes on sale around that time. It's the equivalent of a brick-and-mortar fire sale, though they're not intending to clear shelf space.

Not so much price, but also server activity.
I'm currently crowded with lots of work, and haven't been able to try the L4D2 demo, so i'm assuming it probably won't work on my computer
So would people still be playing the original game after number 2?

I don't even own the first one. So it's 2 for me only.

No. The way L4D2 is being justified is that L4D was basically a mistake which L4D2 apparently fixes. It still doesn't really have enough content to justify the price (Crash Course only added a couple of levels) especially given that it's now a year old, and looks older.

L4D is rubbish anyway. I would MUCH rather of gotten a refund for the 25 i paid (half price), paid 20 for Killing Floor and saved 5 bucks to go on a NBC suit or gas mask :P
Anyway, if you really MUST play l4d i would wait for a month or two for the enevitable half price sale.

High fives and +1's

Hmm, is it?
... Well ....
Nah. Unless it's for free.

Thanks!

Thanks guys
I guess Zombie Panic Source will be my feed of zombie goodness for now........

Try Zombie Master too. It's a lot less polished and lately the quality of the maps are questionable. But the RTS style that the "Zombie Master" unleashes the hordes of zombies is just awesome. Imagine the "Director AI" except that the director is a human player.