I don't think we can say that the N900 is ahead of it's time again, here. Windows Mobile had multitasking.

Then Microsoft listened to what Steve Jobs said about multitasking being bad. So Microsoft announced Windows Phone 7- Now Without Multitasking™!

Just what he'd waited for, Steve Jobs immediately announced that he'd reinvented multitasking and IOS was even better than the better before.

So, dragging it's tail between the legs, Microsoft had to go back on the announcement box and say: "There's gonna be Multitasking in WP7. We just, uhm, didn't get it ready in time cause Ste... somebody hadn't told us yet."

Microsoft did a WTF on multitasking in Windows Phone 7, rendering it unattractive to most WM6 users. And then they did a very late 180, so multitasking is supposedly on the way.

I don't think the N900 can take any credit for being early here, though. My previous Windows phone had both multitasking and a working task manager.

Edit: instead, the N900 can take credit for being the best at multitasking.