I think Parm makes a really excellent point, and I have to say I agree with it.
For techie people like us, who take an overview of consoles and what they can do before making a purchase, the lack of online play at least as good as the 360 can be seen as a major problem for would-be PS3 buyers.
However, a lot of people I'd imagine who wouldn't buy an Xbox or Xbox 360 because "it's not a playstation" have no idea about the delights of online play and as long as the box has PLAYSTATION written on it they couldn't care less.
Sony are shooting themselves in the foot by not providing developers with the tools to add online play for all the launch games, and it doesn't bode well for the future of the console.
As for the launch titles mentioned, I really don't think it'll be a big deal for many people who have been eagerly anticipating the PS3 .. as long as they are not regulars on the (from what I hear fantastic) Xbox Live service.
I don't doubt that given the right tools, developers will make the best of the PS3s online capabilities in time.
I guess it really boils down to personal preference and experience as others have pointed out - if you're used to having online play in every game, you're going to miss it when it's not there, if not (like me), you won't.
I think it's easy to forget that a surprising number of people are still willing to let a company tell them what they want and need, as weird as it sounds, making this less of an issue for hardcore fans as you might think.