Don't worry Jaysit
From the tactical point of view, there is no possibility of this war turning into a Vietnam.
Not even a new Stalingrad (which, we must not forget was a 300.000 citizens city, very tiny if compared with Baghdad).
As I see it it looks more and more like the fall of Berlin in April 1945.
Yet, in April 1945, The most important German General Gottard Henrici (not to confuse with Heirich Himmler) refused to send the 56th armored Panzer division (the last large German Panzer formation) to fight within Berlin. Also, the 9th Army of General Busse went west to join with the German 12th army of General Wenck, and both armies surrendered to the US forces.
Only the SS
forces, the Hitler youth, and the Volksturm (kind of militia) were left to fight the Russians.
I don't know, if the Iraqi leaders will do the same thing (meaning avoid entering Baghdad with heavy forces)
Tanks are not quite helpful in cities, but Baghdad is actually quite similar to Berlin. Very large streets, crossed by a river, with some channels. The similarities are very large. (Baghdad being actually larger than Berlin).
When Baghdad is taken (And there is no doubt about that) it will be the largest city in history to be taken in combat.