Which lens would you use more?

At a wedding shoot? I have a 28-75 f2.8 and i was going to get a 70-200 f2.8 (instead of my 3.5-5.6 now) but i'm wondering if i will really need it?
which lens will be used more? It is only the reception that I'm going to do for a friend and free!
someone said in a earlier post to get a 80-200 f2.8, that lens is cheaper and i could get it in the Nikon brand. Is that the better option than either the Tamron or Sigma in 70-200? Will i really miss those 10mm in between? I do not have a full frame camera.

The 70-200mm will be useful for so many events, sports, kids, etc. And no, you won't even notice the difference between 70mm and 80mm.

70mm starting focal length is not gonna work indoors. You will always need a room in front of the lens to get your focus right. 28-75 is just perfect. 70-200 is only good for outdoor sports, landscape and anything outdoors.

There's very little difference between 70 mm and 80mm. Unless you're looking at tight portraits from a distance, I don't think I'd opt for the longer zoom. If you can see how large the room is, and how close you'd be to the participants, you'll have a better idea of which lens would be more appropriate. I'm not sure about your camera. Do you mean a digital camera with a less than full frame chip, or a 35mm camera that's half-frame, or?

Your 28-75 f2.8 is all you need for the reception really.

From my experience, if you don't have something longer than the 28-75 with you, you will wish you had for half your shots.

If the reception is in Aunt Martha's living room, the 28-75 will be fine. If it is in any sort of hall or banquet room, the 70-200 is a great thing to have. You can grab candids from across the room, without anyone noticing what you are doing. It would also allow you to stay back from the wedding couple's table and still get the shots you need of toasts and that sort of thing. That way you don't block the view of everybody else in the room because you have to stand in front of them to get the shot.

As for which lens… Whatever your budget allows will work better than not having one at all.

I have adopted a Nikon 24-120 f4/5.6 as my standard lens with my D700 and find it superb for both indoor and outdoor work. A word of caution however is that this lens is best at f11 and above which needs an ISO of 1000 for my particular (transport) work hence my use of a D700 which handles noise at this rating very well.

I believe that Nikon has recently brought out a F2.8 version which could be worth investigating but given the results from my D700 I won't be investing in this just yet.