Here is a rumor spec that i got off Download Squad. With Mobile World Congress coming on Feb 15, more details on WinMo 7 will be revealed:

Software-wise, there’ll be a marketplace with ‘try before you buy’ (hooray!), full Xbox integration (why?), support for social networking (via apps, I presume) and… wait for it… no multitasking!

By no means will this be true but if windows mobile 7 takes that route on multi-tasking then it tells us that perhaps multi-tasking might be pretty overrated in terms of how we perceived it.