Q:

Is an unconsumated marriage still a halachic marriage?

If the wedding ceremony is completed and the man and woman are led off to the yichud room -all the formalities are done, the kesubah is signed etc, however is the act is not actually consummated are they still man and wife?
In addition, if any of the steps are left out of the ceremony, ie chuppah , kesubah etc is the wedding valid?

A:

There are two steps to marriage in Judaism: Kiddushin and Nisuin. Once those two are completed, the couple is married.
In our days, the first act, Kidushin, is generally done by giving the Kallah a ring.
The second act is done in a variety of ways (as what constitutes Nisuin is actually a Machlokes). The Chuppah is one such view, the Yichud room is another [and there are others as well].
But the bottom line is: once Nisuin is done the couple is completely married. There is no need for any additional action.

Aside: Here's where your question may be coming from:
The Rambam (IIRC) who holds that Nisuin is effected by Yichud also holds that such a Yichud needs to be one that is ראוי לביאה (a yichud in which the act may be done). For example, if the Kallah is a Niddah, then even if Yichud was done, the Rambam would hold that it is not enough to accomplish Nisuin.
However, even according to the Rambam the act only need to be able to be done. It does not actually have to be done.

