Its only outdated if it fails to meet your needs. To that end, I've found my 08 MBP more the up to the challenges I throw it at and I'm not one of those folks who are waiting.
Most consumers buy a computer when they need one, which is counter to what many folks here are doing. Waiting for the latest and greatest. Of course that means for many, they've been w/o a top rated laptop for several months. I've seen posts here about people holding off in November of 09 because a refresh was imminent. That was 4 months ago.
While I do think we're close to seeing a new machine from apple, I believe many of the folks waiting will under utilize it, that is they've been waiting for arrandale but only to surf the web, email and/or do office apps.