Some differences between MP´s and XP´s and P4s and Xeons are still there, though. All Xeons ship with HT-enabled circuitry, for example.
I´d say that Intel is a much better choice for dual-cpu systems right now. Several reasons exist: the AMD760MP chipset is inefficient and it´s the only chipset available for MPs. The 7505, on the other hand, is a rather robust alternative for Intel. The MPs only go as high as 2600, while the Xeons go up to 3.06Ghz - the consequence is that the Xeons that are not state-of-the-art (i.e, not the 3.06Ghz) are cheaper, and therefore, Intel-based dual-cpu systems equivalent in performance to AMD-based dual-cpu systems shouldn´t be more expensive. So I´d go Intel 2x2.8Ghz on 7505 over AMD 2x2600 MPs on AMD760MP anytime, even if that means paying a little extra.
Check out the latest review, and you´ll get the picture: <A HREF="http://www.gamepc.com/labs/view_content.asp?id=xeon306&page=1&bhcp=1" target="_new">reviews of MPs vs Xeons</A> should be useful to look at.