If you can afford it, i say go for it.
I've owned iMacs, macbooks, macbook pros, and I'll say the mac pro is the best mac i've ever owned hands down.
From the design to the power, to the unlimited possibilities for expansion and what you can do with it, i think its perfect.
As for waiting, this advice is time tested. If you need it, buy it. If you can wait, then wait. But keep in mind that if you wait 3-5 months for the next one. You get it and are happy. But then new tech appears another nine months down the road.
It's like chasing shadows. You buy a mac you like and can afford, and then just enjoy it. With the mac pro, the enjoyment is continuous because you can have fun maxing it out and customizing it long after you bought it.